TW201334839A - Method and apparatus for active control of golf club impact - Google Patents

Abstract

The present invention proposes a method and apparatus for actively controlling the impact between a club head and a golf ball. A golf club head has a face with an actuator material or device mechanically coupled to influence face motion. The face actuation controls impact parameters, impact properties, or resulting ball parameters such as speed, direction and spin rates resulting from the impact event between the face of the club and the golf ball. Further, the apparatus has a control device for determining the actuation of the face. Several embodiments are presented for controlling parameters such as ball speed and direction. The invention can use energy derived from the ball impact, converted into electrical energy, and then reapplied in a controlled fashion to influence an aspect of the face, such as position, velocity, deformation, stiffness, vibration, motion, temperature, or other physical parameter.

Description

Device and method for actively controlling golf club impact force

The invention belongs to the field of advanced sports equipment design, and in particular to the design and function of a golf club head system for controlling the impact force of a club head and a golf ball.

The invention applies control technology and actuation technology to the design of the club to achieve the purpose of improving the hitting accuracy and the hitting distance of the golf club (for example, the No. 1 wood). In recent years, there have been many improvements in this area that have had a considerable impact on the accuracy and distance of the shots that golfers can achieve. These improvements are often focused on the design of passive systems; however, these designs do not have the ability to alter any physical property parameters under active control during swings, especially during impact with golf balls. Typical passive performance improvements, such as head shape and volume, weight distribution and inertial tensor combined component, ball face thickness and thickness distribution, ball face curvature and center of gravity position, all lie in selecting a fixed golf club The best physical and material properties parameters. The present invention is to develop a set of important characteristic parameters (such as the face position/shape/curvature or effective friction coefficient or the stiffness of the ball striking face) for selectively controlling each golf club and club head to the club head. An active control system that reacts to the actual state between the balls. These actual states may be head speed, impact force, strength, impact time and timing, absolute position of the club head or relative position of the ball on the ball striking face, direction of the club head relative to the ball and swing path or parameters, Physical deformation of the ball striking face, or any measurable physical or electrical condition.

This invention focuses on the field of various control technologies, especially the actuation techniques of structural or elastic systems and the control operations of these systems. See, for example, Fuller Control of Vibration, by Fuller, C. R., et al. (Academic Press, San Diego, CA 1996). A specific controllable system uses ultrasonic vibration for friction control (Katoh). Another specific controllable system is to change the effective stiffness of the ball striking face to control the impact force with the ball. The invention is also based on the concept of obtaining piezoelectric energy and/or acquiring synchronizing energy from a mechanical system and an actuating mechanical system. The acquisition of piezoelectric energy is described in the following U.S. Patents: 4,504,761; 4,442,372; 5,512,795; 4,595,856, 4,387,318; 4,091,302; 3,819,963; 4,467,236; 5,552,657; and 5,703.474.

The impact force between the ball and the head can be two elastic bodies with freedom of movement and rotation in space (ie: full 6 degree free body (DOF, each can be deformed in the impact, and both have complete resident quality) The ideal impact force between the inertia tensor and the inertia tensor is explained. The typical initial condition of this motion is that the ball is stationary, and the high-speed moving club head hits the ball with an eccentric point on the face of the club head. The action produces a force (very high force) that is orthogonal and tangent to the contact surface between the head and the ball. These forces combined with time determine the speed and direction of the velocity vector and rotation vector after the ball leaves the face. (hereinafter referred to as the impact force) These interfacial forces are determined by many characteristics, including the elasticity of the two objects, material properties and decay, surface friction coefficient, mass of the object and inertia tensor.

Some of these characteristics and surface conditions can be actively controlled during impact to provide some degree of control over the resultant force. For example, in a specific specific case, the surface can be vibrated in an ultrasonic manner under certain preset conditions to effectively produce a lower coefficient of friction between the ball and the ball striking surface, so that when a trigger condition exists So that the ball can reduce the speed of rotation and fly farther. These triggering conditions may be excessive head and ball impact (excessive ball striking deformation), which means that such high-speed impact will produce excessive rotation and may form more than the required aerodynamic lift, resulting in flight distance. cut back.

In another specific case, the position and/or orientation of the ball striking face can be actively controlled relative to the ball and the club body under certain preset conditions, so that the ball striking face can produce better performance relative to the ball. Achieve more precise ball flight, or offset the rotation of the club head during eccentric impact motion to reduce lateral rotation. These triggering conditions may be highly eccentric impact motions (eccentric strikes) that can be detected by a deformation sensor on the ball striking face or an angular acceleration sensor in the body. The signals from these sensors can be processed to determine the action required to compensate for the ball face and correct the ball flight.

In another specific case, the effective stiffness of the ball striking face upon impact can be controlled to produce a more desirable impact motion. For example, the system can be designed to make the ball striking surface harder on stronger impacts and softer on the ball striking surface in the case of weaker impacts, so that the impact load versus the ball striking face for a particular impact motion The behavior is appropriately modified. This can be achieved by, for example, shorting or disconnecting the line of the piezoelectric signal transducer fixed to the surface or mechanically coupled to the ball striking face: the piezoelectric device becomes softer when the circuit is shorted ( The modulus of elasticity is low and becomes harder when the circuit is broken (the effective modulus of elasticity is higher). A sensor attached to the ball striking surface measures the amount proportional to the impact strength (for example, the amount of deformation of the face, the face of the face, the deceleration of the head, etc.). In the case of a "harder" strike, the shorted piezoelectric device is usually broken to create a harder hitting surface, while in a "softer" blow, the electronic circuit can keep the piezoelectric device in a shorted condition. Lower and therefore lower rigidity.

The trigger signal can be provided by an external sensor or by an actual piezoelectric signal transducer fixed to the ball striking face by cutting off the current or voltage level to the signal converter prior to the triggering event. For example, a circuit using a piezoelectric element as a charge sensor can be mounted on a wire of a signal converter. When the charge reaches a critical level, it can be triggered to cut off the wires from this circuit to effectively force an open circuit state.

An important element that can control the impact of the ball and the head will be able to actuate the system in an advantageous manner. Since the club head and the ball are a mechanical system, this can be accompanied by some force or heat on the system that causes it to produce some change in mechanical and physical properties. This invention is primarily a mechanical actuation technique.

U.S. Patent No. 6,102,426 issued to Lazarus et al. discloses the use of piezoelectric ceramic sheets on skis to affect its dynamic performance, such as limiting unnecessary vibrations at higher speeds or on irregular surfaces. This patent also mentions that it can be applied to golf clubs to reduce vibration or change club stiffness or "affect golf club heads."

The use of piezoelectric ceramic sheets on golf clubs to alter stiffness and affect vibration attenuation is disclosed in U.S. Patent Nos. 6,196,935, 6,086,490, and 6,485,380 issued to Spangler et al. Figure 9G illustrates the arrangement of the piezoelectric element on the golf club head to capture the strain energy dissipated in an electronic circuit to achieve a shock absorbing effect.

U.S. Patent No. 6,048,276 issued to Vandergrift relates to the use of piezoelectric devices to harden golf clubs after drawing energy from swiping and bending the club.

Katoh discussed the use of ultrasonic vibration to reduce friction in an article entitled "Using Ultrasonic Vibration to Actively Control Friction" (Journal of Tribology, Vol. 38 No. 8 (1993) pp 1019-1025). issue. Please also refer to "Frequency-driven micro-mechanisms using ultrasonic waves" by K. Adachi et al. (Wear 194 (1996) pp 137-142).

The present invention pertains to a system for controlling the impact motion between a ball and a ball striking surface by actuating and controlling the position or characteristics of the ball striking face to effect the impact motion between the ball and the ball striking face. It is characterized by the ability to reuse the energy generated and convert it from mechanical energy of the impact motion to electrical energy. Such reuse can advantageously control the impact motion. In a specific specific case, the energy converted from the impact of a piezoelectric element can be converted into an ultrasonic hitting surface deformation/oscillation, which can effectively reduce the coefficient of friction between the ball and the ball striking face. In another specific case, the rigidity of the ball striking face that controls the connecting piezoelectric element at the time of impact causes it to generate a specific behavior according to the set impact characteristic parameter. For example, the hitting surface becomes harder when a strong blow is made, and it becomes softer when it is weaker. All of these conditions apply equally to putters, 1st woods, and irons, while treating all club heads equally.

The ball striking actuator can include a number of actuators (which are not limited in number) that can convert electrical energy into mechanical energy. These actuators include electromagnetic (eg electromagnetic coils) and actuation techniques utilizing electrical and magnetic forces (including magnetic fields that affect material size changes; electrostrictive, piezoelectric, magnetostrictive, ferromagnetic shape memory alloys, shape memory magnets, and Shape memory ceramic material) or any combination of the above. Possible modes of operation include thermal actuators that utilize resistive heating or shape memory alloys that utilize thermal energy to induce phase changes in the material to cause dimensional changes or strain. All of this can be used to convert electrical energy into a hitting surface deformation or a change in the position of the ball striking face in a precisely controlled manner.

On systems using simple actuators, there must be a source of electrical energy (batteries or other power generating devices) to convert the motion or impact energy into electrical energy for use by the ball striking actuator. The system may include a power source, electronics, and an actuator mechanically coupled to the head.

If further defined, it can be a system that connects the signal converter to the ball striking face. This signal converter can use mechanical energy to generate electrical energy and vice versa. Examples of signal converter materials include electromagnetic coil systems, piezoelectric and electrostrictive materials that act under a biased electric field, and magnetic field bias magnetostrictive materials and ferromagnetic shape memory alloy materials, and/or any of the above materials Combination or other composition. These materials will hereinafter be referred to as "piezoelectric materials" and the use of the word "piezoelectric" is not subject to any particular limitation. In systems employing such signal converters, the signal converter component can be coupled to the ball striking surface to cause deformation or movement of the club to generate electrical energy for controlling the impact of the club head with the ball through a reverse actuation function.

Piezoelectric actuators are the most common type of signal converter material. Typically, they can change size in response to the applied electric field and can reversely generate charge in response to the load and stress experienced. They can be used simultaneously as electric actuators and power generators.

The control of the impact force involves applying a force to the club head and/or the ball striking surface to advantageously change the characteristics of the impact motion of the system. For example, if the applied force is proportional to the acceleration of the face, the control will significantly increase the mass or inertia of the system. It achieves this by applying the same amount of force to the head that would be applied to the position under that particular shot surface action. The applied force is applied in a manner that effectively produces forces similar to the system's spring and power and inertial forces. For example, if the force applied to the center of the ball striking face is proportional to the speed of the center of the ball striking face and the direction is opposite, it will effectively act as a buffer at the center of the ball striking face and form a viscous reduction at the center of the ball striking face. Shock absorber. Similarly, if the hitter applies a force that is substantially proportional and opposite the direction of the center of the face, it may act like a spring at the center of the face - effectively enhancing its stiffness. Also, if the applied force is proportional and oriented in the direction of the declination, it may act as a negative phase spring at the center of the ball striking face - an effective reinforcing striking face. An actively controlled system (if the hitter can control the force) can mimic many different dynamic effects in the system. However, the challenge is to develop a system that can apply various types of forces to the system even with certain limitations.

The idea of applying some force that can simulate the type of other forces (usually derived from inertia or mass) is in fact a testament to the force that can be imposed. In such a control system, there may be an arbitrary phase relationship between the applied force and the input, and this relationship may be taken from the frequency. In essence, the function of the control can be a linear or non-linear dynamic system between some of the sensors and the output force applied by the actuator. On a classically controlled system, there is a control system that picks up the output of the sensor and applies the force to the object to achieve the desired effect. This is the general field of dynamic system control, and the more specific is the structural control of the elastic system, which will be defined in this paper.

Ultrasonic (or high frequency) oscillations of the contact surface may result in a lower effective coefficient of friction between the two faces. This oscillation must have sufficient amplitude and frequency to cause the two surfaces to briefly lose contact at least in one part of the oscillation. This interrupted contact reduces the effective coefficient of friction.

An actuator attached to the ball striking face can be designed to excite high frequency oscillations of the ball striking face when driven by high frequency electrical input. If this excitation occurs at or near the resonant frequency of the club/ball face body, its amplitude may be amplified.

In the case of a golf ball impact movement such as a very high normal force during impact, an important requirement is that the acceleration of the ball striking face away from the ball during the oscillating motion should be high enough that the ball does not "catch up" with it. It is possible to cut off the contact of the surface. The acceleration is proportional to the amplitude of the oscillating action multiplied by the square of the excitation frequency. This can be seen as an advantage in the design of the actuation system. Since the oscillating amplitude of an actuated system tends to be flattened piece by piece due to inertia, there is some "discount" between driving at high frequencies and reaching the highest possible amplitude of the array. And this advantage can help balance the friction to control the friction control effect. For example, in the specific case preferred by the present invention, the advantage of stimulating the surface of the ball striking face at 120,000 Hz (connected to the actuating drive described later) can be found.

In systems where no external power source is available, a portion of the impact energy (converted from mechanical energy to electrical energy by a signal converter connected to the ball striking face) can be stored and ultrasonically excited in a high-slot surface mode (ie, with signal conversion) The form of the high-frequency oscillation of the hitting surface of the connected device is sent back to the hitting surface. The energy can be stored in the signal converter material, for example in the form of a charge stored in the capacitance of the piezoelectric material, or can be stored mainly in an auxiliary circuit component electrically connected to the signal converter (eg storage capacitor or tantalum circuit, etc.) ). After a trigger effect releases energy, a drive circuit can be designed to induce a critical time point in the impact motion (eg, a critical time point selected by the control operation) when communicating with the signal converter. The high-amplitude ball striking surface oscillates to effectively reduce the impact friction coefficient between the ball and the ball striking face. The oscillating surface of the ball striking surface and the controlled friction exert a controlling effect on the rotation of the ball, which can be selectively triggered under specific impact conditions (such as high level impact forces).

The departure velocity of the ball can also be controlled by applying a force proportional to the declination of the ball striking face. Through proper signal transmission, these forces can effectively soften the ball striking surface by increasing the duration of the impact, thus reducing the impact load and the deflection of the ball. The lower the ball's deflection, the lower the dissipation due to the inelastic deformation of the ball and the increased recoverable energy of the impact motion, thereby achieving a higher coefficient of restitution (COR) and higher ball speed. Conversely, the impact energy converted to electrical energy can also be dissipated in the selected impact condition to reduce the effective COR.

By selectively applying electric force to simulate the effects of various carefully controlled balls, some of the ball striking surfaces can selectively cause it to deform more than other parts during the impact motion, thereby controlling the departure of the ball. direction. The direction of departure can be controlled because the final ball speed (speed and direction) is determined by the force generated by the elastic impact. Irregular deformation of the ball striking surface (due to unbalanced ball control) changes the normal reaction direction of the ball and thus changes the final direction of travel of the ball. In addition to directly controlling the direction of the ball, it is also possible to indirectly control the direction of the ball by reducing rotation (including side rotation) and thus lateral movement. A similar control function can be achieved by actively locating an activated club face in an impact in response to certain measured impact variables such as the impact position or angular acceleration of the club head (caused by eccentric impact). .

At the same time, it is also possible to apply force to the head to simulate the effect of a higher moment of inertia. In other words, these forces act on the club head in an impact similar to adding a special mass at a particular location. Such forces can be triggered in the event of a missed shot to produce a more straight shot. One way to achieve this can be, for example, to create a force on the club head through the action of a reaction block. The actuator reacts between the head and the reaction block, which reacts in a manner that reduces the rotation of the head during impact. Its function can effectively increase the moment of inertia of the object, so that the ball striking surface can be kept more straight, so the flight path of the ball will be more straight during the impact motion. Since the impact motion is carried out for a limited period of time, we can apply that force to the object for a limited period of time. We can partition a center column and an bisexual ring so that we can actually detect and sense how the head moves relative to the reaction block. Whether it is moving up, down, left or right, the way the ball face is rotated can be used as a perceptron input to the compensator/controller so that the applied force can act on the final face. Make compensation. Either multiple piezoelectric elements or multiple electrode configurations on a single piezoelectric element can be used to detect a wide range of impacts. We can actually determine where the ball hits the ball striking face and use the control circuit to compensate accordingly, such as by slightly rotating the ball striking face to compensate for the rotation of the club head during an eccentric impact. In the specific case we prefer, the piezoelectric element will only output a voltage and it is difficult to determine the actual impact position in each possible impact position. But this is not necessarily a limitation of this invention. We can distinguish multiple electrodes on a common piezoelectric element fixed to the ball striking surface to detect the location of the impact. Such a configuration basically does not differ from fixing a plurality of piezoelectric elements on the ball striking face. The plurality of electrodes thereof may be arranged, for example, in a square array. For example, nine electrodes may be arranged in a 3 x 3 square array on the back surface of the ball striking face. The voltage transmitted between these electrodes to the control circuit can be used to determine the impact position of the ball and to react appropriately accordingly. In the reaction, the voltage of some electrodes on the signal converter can be turned on (as opposed to other electrodes), and the appropriate reaction can be made according to the position of the impact.

The following description assumes a certain understanding of the basic principles, functions, and methods of piezoelectric materials referred to in the "Piezoelectric Ceramics" (Academia Press, 1971) as written by Jaffe, Cook, and Jaffe, and the references cited herein. . The contents of this publication are incorporated by reference in the entirety of this disclosure. Another useful reference in the field of piezoelectric mechanics is the "piezoelectric architecture" (Academic Publishers, MASS., 1993) by H. S. Tzou, Kluwer, which is also incorporated herein by reference.

Actuator and ball striking surface

There are a number of ways to attach the various actuating components and signal converters to the club's ball striking face (ie, the interactive surface between the ball and the club head). The signal converter can be directly related to: 1) relative deformation (elasticity) of the ball striking face, 2) absolute motion (inertia) (using various techniques), or 3) relative between the ball striking face and the head body motion. This article describes eight different methods for correlating an actuator or signal converter with the elastic deformation of the ball striking face or the inertial motion of the club head. In terms of the actuation function, the goal is to maximize the control of the deformation of the ball striking surface with the desired actuation frequency. In the case of a signal converter, the goal is to maximize the correlation with the absolute motion (deceleration) of the club head (or the ball striking face) or the deformation pattern caused by the impact of the club head and the ball striking surface with the ball. . Both of these techniques are related to the kinetic energy or elastic potential energy generated during the impact. This energy is then converted by the signal converter into electrical energy that can be used by the ball striking face or interface. The eight different system descriptions used to correlate the signal converter components with the golf club face are as follows.

There are three methods for connecting the actuator to the ball striking face. The first method is "elastic piezoelectric ball striking surface actuation" in which the dimensional change and deformation of the signal converter is directly related mechanically to the relative deformation between the two structural points on the ball striking face or the ball striking face. This type of elastic actuation is commonly referred to as structural control where the piezoelectric element is (primarily) mounted on or embedded in the structure to create an advantageous structural deformation. The specifics of the four elastically linked actuators are as follows:

Concept 1 - The piezoelectric wafer is directly attached to the ball striking surface to promote bending, as shown in Figure 1.

Concept 2 - Piezoelectric stack and/or piezoelectric tube is mounted on the ball striking face as shown in Figures 2a, 2b, and 3.

Concept 3 - The piezoelectric element is placed between the ball striking face and a hard backing plate, as shown in FIG.

Concept 4 - The piezoelectric element acts in the direction of the shear force and is placed between the ball striking face and a solid constraining layer, as shown in Figures 5a, 5b.

The second actuator is coupled to the ball striking face by the absolute motion of the actuator and the ball striking face or by the absolute motion caused by the inertial force generated by the ball striking face and the movement of the club head upon impact with the ball. These methods typically require a reaction block and an actuator or signal converter element that acts between the reaction block and the ball striking face. The manner in which these ball striking faces are joined is usually related to the proof mass or the reaction block actuator. The concept of this type of method is described as follows:

Concept 5 - Direct piezoelectric connection between the ball striking face and an inertial mass, as shown in Figure 6.

Concept 6 - The action between the ball striking face and an inertial mass amplifies the piezoelectric bond, as shown in Figure 7.

Concept 7 - The bisexual piezoelectric element is attached with a tilting mass and mounted on the ball striking face as shown in FIG.

The third actuator is coupled to the ball striking face by an actuator coupled between the ball striking face and the club body. The actuator may be a single one or one of several actuators on a parallel load path disposed between the ball striking face and the body. This method is similar to Concept 3, but the ball striking face is more like a rigid body that can change position but cannot be deformed like Concept 3. The signal converter disposed between the ball striking face and the body will withstand most of the load between the ball striking face and the body and can participate in the impact motion to a considerable extent. In addition, the actuation causes a change in the position of the ball striking face relative to the body, which essentially uses the body itself as a large reaction block to cause a change in position or orientation of the ball striking face during impact.

Concept 8 - Piezoelectric signal converter is placed between the ball striking face and the club body, as shown in FIG.

In the application of the signal converter, in order to generate the maximum available usable power and maximize the available connection (for example, to generate high-amplitude and high-frequency ball striking oscillation for rotation control), it is better to have good with the following two aspects. Correlation: 1) impact deformation pattern and 2) high frequency mode. In applications where the position of the ball striking surface changes (rather than the application of friction reduction), it is best to have a good correlation with the following two aspects: 1) impact load pattern and 2) impact between the ball striking surface and the body over time. motion.

Usually in the concept of elastic joints (1-4), the motion/load of the ball striking surface creates a load on the signal converter material and produces the corresponding electrical energy. Conversely, the electrical energy applied to the signal converter controls the motion of the ball striking face. It is best to have a high level of electromechanical correlation between the ball striking load/motion and voltage and current. This association may be measured by a fraction of the mechanical energy input by the impact being converted to stored electrical energy (eg, stored on a piezoelectric element or a shunt), or vice versa, to induce deformation of the striking surface. The electrical energy input is converted to a fraction of the strain energy.

Concept 1

In this hitting surface joint case, a piezoelectric element (21) that can produce a change in planar size (also referred to as a 3-1 actuator, although various cross-cut piezoelectric wafers or complex actuators can also produce planar dimensional changes) Attached to the plane of the ball striking face (10) or embedded in the sphere. The actuator can also be packaged in a known related art. Since the actuator is not properly positioned on the centerline, it will interlock with the bending deformation of the ball striking face and will cause a bending couple (105) on the ball striking face when energized. In addition, in the case of the embedded actuator close to the center line, it is interlocked with the deformation of the plane instead of the bending, and the interlocking with the plane deformation movement can be forcibly achieved by the parameter in the case of large deformation. The actuating load can be thought of as a combination of the planar deforming force acting on the ballistic surface of the actuator on the ball striking face and the bending couple (105) (as shown in Figure 1). Some important parameters include the spatial extent (length) of the actuating element and its thickness. The x-y range in space is determined by maximizing the shape of a particular desired face shape. A good bond may be equal to the transverse strain field multiplied by the electric field multiplied by the integral of the piezoelectric constant of the actuator. It will be connected to certain shapes, so some structural modalities will be maximized in the shape and range of the corresponding actuator.

For example, an axially symmetric plate covering a circular actuator with a certain radius and the second symmetric plate mode (a pitch circle) will extend to the node radius in the range of the active disk but no longer continue to stretch. to reach maximum. If the radius of the disk is greater than the radius of the pitch circle, materials outside the pitch circle will experience strains that are opposite to the positive and negative materials within the pitch circle and will partially offset the piezoelectric response when the entire disk meets.

For specific cases where a signal converter is connected and it is desirable to obtain energy from the impact and possibly to excite a high frequency mode (to control friction), the actuator must be designed in such a range and thickness that it can: 1) The resulting shape (substantially the first modal deformed shape of the center shot) correlates; and 2) the deformed shape associated with a high frequency modality correlates.

Since the ball striking face is a relatively thick structural member, it is recommended to use a relatively thick piezoelectric element during manufacture, such as approximately 1 mm to produce sufficient action on the 2-3 mm thick ball striking face. A typical ball striking design shows a piezoelectric element with a diameter of a few centimeters (1-5) to achieve the desired dual target: the first impact shape that produces energy and the high frequency mode to be generated. Friction control. A typical design for this type of ball striking face is a 3-1 mode piezoelectric disk through which the electric field is applied and the disc is fixed to the ball striking face 10 (as viewed from the inside).

It must be noted that the piezoelectric element 21 can be packaged in a polymeric sealant and the possible electrodes distributed over this polymeric sealant or flexible circuit. The distribution of the electrodes can define various different zones of action and form a partitioned, uniform, or interdigitated electrode profile in a possible curvilinear distribution pattern. An important factor is the need to maximize the electromechanical connection between the piezoelectric element and the deformation of the ball striking face (as defined above).

Concept 2

We will now describe our preferred method and system for the connection of the actuator or signal converter to the ball striking face. In this method, the piezoelectric element 21 (preferably a stacked piezoelectric element, but also an electrostrictive element or a magnetostrictive element or any of the aforementioned actuation or signal converter techniques) is attached to the ball striking face (although It is fixed on the ball striking surface by the housing 12 or the supporting structure). For a detailed description, please refer to the cross-sectional view of the components of Figures 2a and 2b. Among them, the club 62 is connected to the head body 11.

In this case, the piezoelectric element 21 is designed to be stretched or resized in response to input electrical energy (voltage or current). If it is a system using piezoelectric, there are many ways to achieve this. In particular, we can use a piezoelectric stack to correlate the applied voltage with the change in length. This can be referred to as a 3-3 junction and is a high mode of piezoelectric material reaction. A 3-3 stack consists of a layer of piezoelectric material and electrodes between the layers, aligning the electric field with the central axis to produce a longitudinal piezoelectric effect. See the secondary assembly (piezoelectric end cap assembly 15) in Figure 18 for details. The actuator may also employ a lateral extension configuration in which the electric field is applied in a direction perpendicular to the longitudinal axis or a 3-1 actuator. This can be achieved by a rod that is placed on the opposite side along the length of the rod, or a tubular actuator that applies a load along the length and the electric field is applied through the tube wall thickness from the inside and outside of the tube wall. In this regard, a variety of different axial extension actuator/signal converter configurations can be employed.

The second component is a housing 12 for creating a mechanical connection between the back end of the actuating element and the ball striking face. The deformation of the ball striking surface causes relative movement between the point at which the actuator is in contact (possibly in the center of the ball striking face) and the point at which the casing is fixed on the ball striking face (as shown in Figure 2a, at each point of application 106). . The rigid housing then transforms this relative motion into relative motion between the ends of the actuator. The housing 12 thus acts as a mechanically coupled character that causes the change in length of the actuator to be associated with different motions (deformations) of the ball striking face. Therefore it belongs to the elastic link of the ball striking face.

The most important thing is that the housing must be rigid (theoretic stiffness, at least similar to the rigidity of the piezoelectric element), because any expansion of the housing under the actuating load will reduce the transmission to the ball striking face and deform the ball striking surface. load. To achieve this, we should consider limiting the use of a soft housing. Secondly, when the moving element starts to stretch, the housing will bear a small load and just start to tighten, thus causing a small deformation of the ball striking surface. In fact, the condition is usually that the rigidity of the casing must be at least 1 to 20 times larger than the ball striking surface when the casing connection and the actuator connection are subjected to equal but opposite loads to ensure that the load can be effectively deformed with the ball striking face. It is not the extension of the casing) that makes a connection. The housing should also be as light as possible to avoid a substantial increase in mass and thus a significant change in the center of gravity of the club head or its inertia tensor.

The housing 12 is formed by a conical or cylindrical casing wall 52 and a backing plate (end cap 13) for making contact with the actuator, and has a rounded end which is in contact with the ball striking face through a ring 56. See Figure 17-19 for a detailed illustration of the Concept 2 preference case. The housing 12 can be joined by threading 29, or welded, or secured to the ball striking face using any other technique. The end plates can be permanently fixedly machined into a single piece with a shell wall or designed as a screw joint (end cap 13) to facilitate assembly of the actuator system and for removal. When considering the rigidity of the casing under the operating load, all of the casing's undulations, including the backing of the casing, or other deformations must be taken into account. This is why the tapered construction is extremely efficient, which reduces backing plate bending and provides a more direct load transfer path for the ball striking face. Typical dimensions are shell wall (52) ~ 1mm, shell back (end cover 13) ~ 3mm. The signal converter assembly (piezoelectric end cap assembly 15) composed of the piezoelectric laminated actuator (piezoelectric element 21) and the end piece (23) is ~16 mm long (total length) as shown in Fig. 18 (10 mm of which is actuated) Material 21). The cross section is a 7mm x 7mm square stack or a preferred 9mm diameter circular stack.

Of particular importance in design is the choice of the point of contact of the housing and actuator with the ball striking face. If the actuator is placed in contact with the center of the ball striking face, the housing may be fixed to the ball striking face at a discrete distance from the center or at a continuous (circular) ring (fixed radius). This choice of fixed radius is very important to maximize the performance of a particular control application. The end piece 23 is preferably made of steel or aluminum or other extremely hard material and has a slight curvature (convex surface 26) to provide concentration with the ball striking face 33 and the back of the casing 12 at a bending point (indentation) close to the machining. Point contact.

In the particular case of friction control, one of its goals is to excite high frequency oscillations as previously described. Therefore its diameter must be carefully selected to meet the following requirements: 1) a good correlation between the shape of the impact deformation and the generation of electrical energy; and 2) a good correlation with the high frequency mode. This can be achieved by setting the connection radius to approximately the radius of the antinode of the favorable ball striking face mode. The antinode should be preferentially reverse deformed at the center to expand the relative motion.

The design optimization considerations are as follows - if the radius is too small, the piezoelectric center force and the reaction force will be very densely applied to the ball striking surface. The ball striking surface is very rigid between these separated points and can only cause a slight movement. Conversely, the differential deformation between these fixed points in the shape of the impact deformation is also very small, because it is determined by the curvature under the impact load, so that only a small amount of voltage can be generated during the impact. If the radius is too large, it will have a good correlation with the impact, but it will be difficult to construct a rigid shell structure and it will be difficult to generate high amplitude in a high frequency mode, because the modality of the shell will start to join and be effective. Reduce the dynamic rigidity of the housing. In the preferred case, our face-to-face ring 56 has a diameter of approximately 35 mm because it optimizes the expansion of the dual target, ie the connection between the impact of the ball and the deformation of the ball face and at ~ The relationship with the high frequency ball striking mode at 120 kHz.

When evaluating a particular design, the impact surface and the stresses of the housing and actuator at the time of impact must be considered. Extremely high stress levels can shorten the fatigue time of the housing. In addition, the high compressive stress applied to the actuator upon impact with the ball may also cause permanent "depolarization" of the material, i.e., permanent impairment of the actuator characteristics. The mechanical system must analyze its load in various impact motions with the ball to determine if these critical load levels do not exceed the life of the casing or the stress induced polarization of the piezoelectric element.

We can place the piezo element at the center or weld a payout bolt at the center of the ball striking face and use a cylindrical piezo element or radiantly separate the plurality of piezo elements (eg multiple stacks) from the bolt. As shown in Figure 3. We can relate to the lowest impact deformation shape and high frequency mode shape in the 踵 configuration. Since the axial configuration relative to the normal of the ball striking face is employed, it is possible to facilitate the adjustment of the signal converter component by means of an anchor bolt 205 positioned at the center of the ball striking surface for screwing a preload bolt 206 and the back plate 212. The preload of the electrical component 21) can also be conveniently designed for the desired surface excitation amplitude.

Concept 3

The third specific thing is shown in Figure 4. In this case, the piezoelectric element 21 acts between the center of the ball striking face 10 and a rigid backing (support) structure 207. The support structure must be very rigid to achieve the desired high reaction force - for example 1-10 times the stiffness of the ball striking face, so that the action can cause deformation of the ball striking face (rather than the backing structure). Intermittent contact may be employed between the piezoelectric element and the ball striking face. Due to the high rigidity requirements, the backing structure may also be heavy.

In Concept 3 as shown in FIG. 4, a piezoelectric element 21 disposed between the ball striking face 10 and the backing structure 207 then transmits the interface load of the ball striking face to another portion of the club head body 11 ( That is, the rear part) or the periphery of the ball striking face. When the ball striking surface moves about 1 mm in the impact with the ball and compresses the piezoelectric element, it generates a charge and can be used to power the system and, for example, energize an ultrasonic device. Because it generates electrical energy through the relative motion and load between the ball striking face and the backing structure, it must be designed with a rigid backing structure to withstand the motion of the ball striking face and provide a very high piezoelectric load. If the backing structure is too soft, it will deform with the ball striking surface under a very heavy load and cannot be actually pressed or applied to the piezoelectric element. This also means that there is no good piezoelectric electromechanical connection with the impact.

This concept is related to the axial motion (or normal motion) of the deformation of the ball striking face. This can be achieved by a single stacked element or a single piezoelectric element that is in a direction of pulling force and having a load substantially in line with the surface movement of the ball striking face. In such a configuration, the actuator employs a 3-3 actuation mode. It may be a 1-3 modal actuator or may be a tubular element having electrodes distributed on the inner and outer tube walls as described in Concept 2, so that the direction of the stress is perpendicular to the direction of the pulling force. The basic reaction force will try to prevent the movement of the ball striking face, so the backing structure must be rigid enough to achieve this effect. This requirement for rigidity may make the structural element relatively heavy and can be designed to be relatively close to the center of gravity. However, the added mass will reduce the moment of inertia of a fixed-quality club head because less mass is available at the periphery.

In another example of Concept 3, the piezoelectric element is initially not in contact with the backing structure. Upon impact with the ball, the deformed ball striking face causes the piezoelectric element to contact the backing structure and apply a load to the piezoelectric element. For example, the piezoelectric element mounted on the ball striking face may be half a centimeter away from the backing structure so that it does not come into contact until it hits the ball. In this way, the system can be designed such that only high amplitude impacts can load the piezoelectric element and trigger control functions. Such impacts have been applied to structural systems for damping. It can also be used to change the effective stiffness and effective ball striking surface reaction and thus the speed of the club head under different ball impact loads. For example, if there is a small gap between the ball striking face and the backing structure (even if there is no signal converter here), a low-intensity impact may leave the ball striking face unsupported without pressing contact. In the case of a high-intensity impact, the impact surface and the backing will contact during the impact; and the backing structure will support the ball striking surface and reduce the deflection of the ball striking surface.

Concept 4-shear mode piezoelectric

In the foregoing concept, the load applied to the piezoelectric element is mainly applied in the form of normal stress. In Concept 4, the piezoelectric element is pressed in the direction of the shear force and is associated with the electric field by the shear mode of the piezoelectric action. For more information on shear modes and the main modes of piezoelectric signal converters, see the product documentation for Piezo Systems Inc. in Cambridge, MA. The shear mode piezoelectric element is related to the shear stress on the polarization axis of the material, as shown in Figure 5a. For example, if polarization occurs in the x-direction of the material, shear stress will occur in the x-z plane around the y-axis, as shown in Figure 5a. In this piezoelectric mode, the electric field (E) is applied perpendicularly to the polar axis x. This piezoelectric reaction mode is sometimes referred to as a 1-5 mode of action. Among them, the dotted line is the state before the undeformed shape.

In Concept 4, this mechanism utilizes a shear-mode modal piezoelectric element whose actual effect is very similar to that used to mitigate the vibration response of a curved structure. The piezoelectric element 21 predetermined to withstand the load in the shear direction is located between the ball striking face and a rigid backing layer (referred to as a constraining layer) 208. When the ball striking face is bent under the impact load f1, as shown in Fig. 5b, the constraining layer prevents this bending deformation applied in the middle of the piezoelectric element in the shearing direction; wherein the left side is undeformed and the right side is subjected to impact deformation. In Concept 4, one or more shear modal piezoelectric elements are located between the backing layer 208 and the ball striking face 10, as shown in Figure 5b, such that it produces a piezoelectric element when the ball striking face is bent. A shear stress that can be associated with the electric field through a piezoelectric transducer. In a typical configuration, the electric field will be in line with the surface normal and the 1-5 modal piezoelectric elements will be polarized in the plane of the ball striking face. For example, one of the components can be placed at a high curvature point on either side of the backing plate, and a rod or backing plate is used as a constraining layer between the piezoelectric elements. When the ball striking face is deformed, the lever will attempt to avoid deformation and this will exert a large shear load on the piezoelectric element through the actuated 1-5 mode.

In another specific example, the shear modal piezoelectric element is a ring that is polarized outwardly or inwardly toward the radial direction. The ring can be fixed near the center of the ball striking face. The electric field acts through the thickness of the ring between the ball striking face and the constraining layer. In this case, the constraining layer would be a disc with the same outer diameter as the ring and the circumference connected to the ring. This is an axisymmetric version of the concept described above, which acts to cause the drum surface to interact with the piezoelectric element like the motion of the ball striking face.

The applied shear mode is a very effective and high coefficient of connection and high mode of the piezoelectric signal converter. The coupling coefficients of the 3-3 actuation mode and the 1-5 actuation mode are very similar. The joint coefficient can be broadly defined as the fraction of the mechanical energy input that is converted to electrical energy under a predefined load cycle.

Concepts 1, 2, 3, and 4 are all elastic connecting systems, and piezoelectric elements are pressed by the relative deformation between two parts of an elastomer. Since the ballistic surface piezoelectric system is part of this elastomer, the deformation of the ball striking surface causes piezoelectric deformation. In Concept 1, when the ball striking face (an elastomer) is deformed, it also causes the piezoelectric element to deform (because it is fixed on the ball striking face). Concept 2 uses a support structure housing that is connected to the ball striking face at a position different from the piezoelectric element (for example, the piezoelectric element is in contact with the ball striking face at the center and the casing is transmitted through a ring of a set radius outside the center). Contact with the hitting surface). Due to the use of different contact points, the relative motion can effectively compress the piezoelectric element. In this way, the piezoelectric element is linked to the ballistic surface motion. In Concept 3, the deformation motion of the ball striking surface compresses the piezoelectric element disposed between the ball striking face and the backing structure. In Concept 4, the deformation of the ball striking surface induces a shear stress on the piezoelectric element. All of these concepts rely on the association with the elastically deformable branch representing the ball striking face/body structure of the golf club head. Therefore, these concepts can be considered as a whole with an elastic connection with the signal converter.

Concepts 5, 6, and 7 - Inertial Link Concept

The next category (including concepts 5, 6, and 7) represents the way in which different loads and signal converters are connected (using the inertial force at the time of impact). These concepts take advantage of what is needed to accelerate a mass that causes it to press on the piezoelectric element. Therefore, the load on the piezoelectric element is an acceleration function rather than a relative deformation of the ball striking face. In the simplest case, there is a reaction block 209 (sometimes referred to as proof mass) and a piezoelectric element 21 disposed between the reaction block and the ball striking face 10, as shown in FIG. This system is similar to a mass spring system in which the piezoelectric element is similar to a load-bearing spring. The moving ball striking face is similar to a moving base in a spring mass system. When the ball striking surface moves in the impact with the ball, the inertial force will prevent the reaction block from moving and the piezoelectric "spring" will be pressed due to the differential displacement between the ball striking face and the mass. When it is under load, it generates a charge and then can be used to control the voltage on the ball striking face, as described later.

Of these concepts, the most important thing is to have a good connection between mass and piezoelectric "springs" and the impact surface motion during impact. When the ball striking face moves at a slower speed than the cycle of the first natural frequency of the spring mass system, there is less relative motion between the ball striking face and the mass so that the pad load is also less. In this case, the mass will move with the ball striking surface because the spring force of the spring is much larger than the inertia resistance. In other cases, if the ball striking surface moves very quickly, the mass will not respond and the piezoelectric "spring" will be pressed due to the amount of movement of the ball striking face. Therefore, the load on the piezoelectric element and the amount of load associated with the motion of the ball striking surface depend on the relative mass of the system and the spring constant and the time scale of the force applied.

To illustrate the behavior of the system, imagine the impact surface as a collision-like movement. When the sine wave moves, the center of the ball striking surface moves inward under the load of the ball for a distance (about 1 mm) and returns to the normal position within a certain period of time called the duration of the impact. If the impact movement continues In milliseconds, it will coincide with a half-cycle input waveform equivalent to a 1 kHz input. If the piezoelectric element 21, the reaction block 209, and the spring (the ball striking face 10) have a natural frequency significantly greater than 1 kHz, the system will resemble a rigid body under the movement of the base (ball striking face). In this case, the piezoelectric element does not have many relative deformations. The relative motion is equivalent to the strain that the piezoelectric element encounters and the voltage that the piezoelectric element is subjected to when it is broken. Therefore, the open circuit voltage that can be reached during an impact drops to zero at very low frequency inputs (long-term impact and rigid piezoelectric mass systems). It will rise to a resonance peak when the input is as large as the time constant of the spring mass system, as the ball striking face remains as it should. If the first fundamental mode of the spring mass system is below the applied frequency, the piezoelectric element will be subjected to a relative deformation between the moving face and the inertial mass as the ball striking surface moves. This is because the mass cannot move at a fast enough speed to react to relatively high frequency ball striking motion.

To this end, a cubic piezoelectric element of 1 cm x 1 cm x 1 cm is typically used with a mass of typically 10 g, and a frequency in the range of 20--40 kHz should be obtained. Unless a very large reaction block is used, it may be too rigid to be in good contact with the hitting surface motion of ~1 kHz. This also means that the designer must try to build a system that is less rigid and supports the mass of the piezoelectric element with less effective rigidity. If the design is good, the natural frequency of the mass piezoelectric will be the same, so it can be well connected with the impact of the ball.

To achieve such frequency tuning, the designer must make the piezoelectric element thinner to make it softer or use a mechanism to effectively have a lower spring constant. Concepts 6 and 7 shown in Figures 7 and 8 respectively show some proof of this mechanically amplified piezoelectric signal converter design. These concepts work with the effective spring constant of the lower piezoelectric element (below the stacked elements). Stacked components can be very rigid. This mechanical amplification increases the stroke of the piezoelectric signal converter and reduces its resistance, essentially reducing the effective stiffness of the signal converter, reducing the proof mass or the spring stiffness between the reaction block and the ball striking face wall.

If the surface of the ball striking face moves at a slower speed relative to the effective vibration of the effective piezoelectric spring and the mass system, the piezoelectric element will have relatively less deformation and generate less charge. If it moves at a faster speed with respect to the time constant, the piezoelectric element is subjected to compression by a substantially bending amount of the ball striking face. To get the energy from the piezo signal converter, the question is how do you design the spring and how much mass to use? If the spring and mass have a natural frequency that matches the time constant of the ball striking motion (eg The time constant of ms), and you want the natural frequency of this spring mass system to be about 1 kHz, to amplify the load on the piezoelectric element to the maximum. At high frequencies, the mass is more like an inertial reaction block. The piezoelectric element pushes the reaction block away. This produces a direct surface motion excitation on the ball striking surface through the force between the reaction block 209 and the ball striking face 10.

Concept 5 has the obvious problem that the piezoelectric element is directly connected to the mass and causes the system to be too rigid. A large mass is required to obtain an appropriate natural frequency range that is most suitable for the impact of the ball. There are many techniques that can reduce the rigidity of the piezoelectric element through mechanical design. For example, a press bar composed of a very thin small-diameter column can be embedded in an epoxy resin to reduce the effective rigidity but still maintain an appropriate piezoelectric charge coefficient. This is called a 1-3 piezoelectric composite. A composite can also act with a particle composite using piezoelectric particles in an epoxy resin. By selecting the appropriate particle volume fraction, the signal converter can be designed to be a less rigid material. Another method that can reduce the effective piezoelectric spring constant without sacrificing the coupling coefficient is other configurations of the piezoelectric system, such as mechanically amplifying the piezoelectric element. Concept 6 shown in Figure 7 illustrates the general concept of reducing the effective stiffness of an enlarged piezoelectric mechanism with a mobile amplifier 210. Thousands of different types of mobile amplifiers can handle piezoelectric motions with extremely large forces and very small strokes and convert them into larger, but less powerful outputs. Basically, the effective coupling factor of the mechanically amplified piezoelectric mechanism is always lower than the effective coupling coefficient of the piezoelectric mechanism itself. Concept 6 presents a method using the so-called telescopic tension piezoelectric concept. In this case, the axial deformation of the motion amplifier (toward the direction perpendicular to the ball striking face) produces horizontal motion and deforms the piezoelectric element. When the piezoelectric element is changed in size to both sides (i.e., when the length of the piezoelectric element is shortened), it is pushed or pulled between the reaction block and the face. Magnification can be any number between 2 and 100, and minimal motion can make the system act extremely. A mechanically amplified piezoelectric actuator produces a larger stroke and less powerful output, so a softer spring can be used between the ball striking face and the applied mass to reduce the required reaction block, if no mechanical Zoom in, this will be much lower than the required quality.

Concept 7 shown in Fig. 8 is a design using a curved body. It can be understood that the bibly curved body 211 is a rectangular strip having one interlayer sandwiched therebetween and two piezoelectric elements on both sides; sometimes there may be no intermediate interlayer and only two piezoelectric elements. The piezoelectric element can be energized such that it produces a deformation in which the upper side expands and the lower side contracts, which causes the element to produce a bend similar to that of a bimetallic strip (due to different thermal expansion coefficients of the upper and lower layers). The output of this bisexual curved body 211 is the bending of the force and the front end. It is a flexural modal actuator that converts very small piezoelectric motions on the plane of the bisexual body into extremely large front end bending motions. It works in a manner similar to a mobile amplifier. Typically, the bisexual body has a greater amount of front end bend than the axial travel piezoelectric element. Basically, the amount of bending of the front end of the strip representing the bisexual bend is converted into an axial compression or stretching motion on the piezoelectric element. They are typical 1-3 modal elements with a piezoelectric wafer with many electrodes on it and a load applied to the plane of the curved element. Some people have used piezoelectric fiber synthesis (PFC) actuators as the bipolar piezoelectric layer. These PFCs can be configured to apply an electric field to the plane of the system using crossed electrodes while the fibers on the system plane are associated with a planar electric field. Two pieces of piezoelectric fiber composite can be fixed to each other (bonded or laminated) and designed as a bisexual bend. This is an element that has a high coefficient of coupling while having better force deflection characteristics. In this concept, this amphiphile is typically disposed between reaction block 209 and ball striking face 10.

Figure 8 shows a single amphiphile with the proof mass set on one side. You can also use two sets of bisexuals that are opposite each other. The characteristics of the dual-body signal converters make them as efficient as electromechanical signal converters. In addition to a simple rectangular planar shape (and therefore a fixed width), this bisexual strip can also change its width and/or thickness as the length of the strip. In fact, it would be advantageous to make the bisexual body tapered, so that it is narrower at the root and narrowed down piece by piece until the point where the load is applied. This allows the system to be more efficiently linked to the motion of the front end. It also has great advantages as the length of the strip of the bisexual strip changes its thickness, preferably at the root and thicker on the outside. This allows the stress in the device to be amplified to a maximum and the mass required for the device to be minimized to achieve a certain level of energy coupling. You can homogenize the stress level of the piezo element so that there are no areas with extremely heavy loads and extremely light loads on the piezo element. A relatively uniform load level can increase its effective coupling factor.

Bisexuals do not have to be rectangular, they can also be tapered or rounded. They may have different thicknesses, and some of them are curved in shape. Piezoelectric bisexuals have many different appearances. Pay particular attention to the possibility of using a disc-shaped (circular) bi-sex design. The piezoelectric bisexual disc can be fixed to the ball striking surface by a fixed column at the center of the disc, and the proof mass is fixed to a ring of the piezoelectric bipolar outer ring. The electrodes on the bisexual body can be axially symmetric and uniformly distributed or fanned on the circumference (sheet-shaped segments) so that the piezoelectric element can be actuated to generate or react to different tilting actions.

The specific matter of Concept 5 is shown in Figure 6. The piezoelectric element 21 acts between the center of the ball striking face 10 and a reaction block 209 which is sized such that the first natural frequency of the mass on the piezoelectric element is equal to the duration of the impact (tuned). This means that if a lighter reaction block is used, it is necessary to use a piezoelectric element that is enlarged or less rigid. It is a challenge to fabricate piezoelectric components that are soft enough to withstand extremely high impact energy but are hard enough to generate very high forces at high frequencies. It may require a heavier reaction block.

The specific matter of Concept 6 is as shown in FIG. This is a concept similar to Concept 5, in which a mobile amplifier 210 piezoelectric actuator is used instead. The mobile amplifier 210 can convert a smaller pressure electric drive into a larger relative motion between the center of the ball striking face and the reaction block. This solves the problem of impedance mismatch, but the organization can be heavy and more complex.

The specific matter of Concept 7 is as shown in FIG. A bisexual bend 211 acts between a reaction block 209 and the center of the ball striking face 10. It is similar to concepts 5 and 6 but uses a bimodal piezoelectric element between the ball striking face and the reaction block. It may use an axisymmetric bisexual disc and an annular reaction block, or multiple rectangular or triangular bimodal strips and multiple reaction blocks. We must match the first mass natural frequency with the impact motion tuning and then the electrode partition distribution to help locate the impact position of the ball on the ball striking face. It will have an indeterminate high frequency force output.

Concept 8 - Actuator is connected between the ball striking face and the body

The specific matter of Concept 8 is as shown in FIG. In this case, the piezoelectric element 21 or the signal converter connected by the electric wire 22 is provided between the head body 11 and the ball striking face 10. In this way, the load between the ball striking surface and the body during impact can be converted into electrical energy by the signal converter during the impact and the ball striking surface can be controlled by the selected signal converter component to change its positioning relative to the body. . These actuations can be used to change, for example, the rotational position of the ball striking face relative to the body to counteract the rotation of the system caused by the eccentric impact.

This system configuration can have multiple modes of operation. The first is virtual static positioning. In this mode of operation, the ball striking face is repositioned from its original position to a new position relative to the body and the ball. For example, the angle of the face of the ball can be slightly adjusted during the eccentric impact motion. The angle can be corrected in advance to reduce the missed distance - for example, by correcting the direction of the face to compensate for a positive or recurve ball. Its benefits are obtained by changing the static (on impact motion) positioning of the ball striking face.

In another mode of operation, the ball striking surface is repositioned during the impact motion so that the induced motion itself has a desired effect on the impact result. For example, the ball striking face may move in a tangential direction (perpendicular to the normal of the ball striking face) such that the tangential velocity of the ball striking face in the impact can be rotated by the friction between the ball and the surface now moving in the tangential direction. Have a favorable influence. The ball striking face may be forced to produce a tangential velocity having the effect of reducing or increasing the rotation of the ball due to the impact motion. This rotation control can have a certain impact on the subsequent flight of the ball or the bounce and rolling behavior after the ball touches the ground.

In a particular example, the ball striking face can be moved upwardly in a tangential direction to the normal axis of the ball striking face during the impact motion. This can be controlled so that it only occurs during higher impact movements (otherwise it will produce a rise and a high rotation during the impact). As we know, this excessive rotational speed can cause excessive lift and reduce flight distance. By the same standard, the speed of upward movement may be a fraction of the tangential speed of the ball. In this case, there will be less relative motion between the surface of the ball and the surface of the ball striking face, which will cause the ball to produce less upward rotation upon impact and thus increase the distance during flight.

Specific examples of current preferences (concept 2) Principle of action

Due to our intermediate design goals, we designed the club head to convert the impact energy into a high frequency, high amplitude club face vibration. The high frequency excitation of the ball striking face can reduce the effective coefficient of friction of the ball striking face and the ball by the techniques mentioned in the reference of Katoh and Adachi and the known literature. The effective friction coefficient between the ball striking face and the ball which is reduced in the sway of the ball striking surface can reduce the rotational motion caused by the frictional contact of the ball with the ball striking face during the impact. The simulated flight behavior of the ball has been shown to reduce the rotation of the ball due to the impact and increase the flight distance of the ball due to the increase in effective ball speed. These conditions are associated with a higher effective ball speed (i.e. - higher head speed and/or higher headwind). Under these circumstances, the excessive lift caused by the high-speed rotation of the ball will form a flying trajectory, which will result in a considerable flight distance reduction. Studies have shown that at the same high relative speed, if the ball is reduced by 25% of the rotation, the flight distance of 10-20 yards can be increased.

Reducing the friction between the ball and the ball striking face also reduces the side spin caused by the impact of the ball. Reducing the side spin of the ball can reduce the lateral range dispersion of the ball and increase the accuracy of the shot. It is therefore an intent of the present invention to provide a system that can produce the necessary surface oscillations on the club face to achieve the benefit of reducing the rotation of the ball. This system only controls when a high-speed impact that reduces the oscillation of the rotation (suppressing unwanted transitional rotations) is triggered. Yet another aspect of the present invention is to supply electrical energy to the friction reducing control system without the need to use an external power supply (e.g., a battery) with the available energy generated entirely from the impact between the golf club head and the ball.

Multiple simulations have shown that club face oscillating with a high frequency of 5-10 microns and close to or exceeding 120 kHz can significantly reduce the ball's rotational speed. The impact simulation of the ball and the club is shown in Figures 12 and 13. Figure 12 shows the voltage/time transition relationship of a piezoelectric signal converter that is interlocked with the ball striking face during an impact. The voltage will continue to rise until a critical trigger level (set in the electronics) is reached, at which point it will oscillate an oscillation that has been tuned to a favorable ball striking mode (120Kz). These high frequency oscillations (as shown in Figure 13) reduce the coefficient of friction and tangential force between the ball and the ball striking surface - thereby reducing the spin speed and the ball's rotational speed at impact. Curve C in Fig. 13 shows a voltage/time transition relationship similar to that shown in Fig. 12. Fig. 13B showing the tangent (friction) force between the ball and the ball striking face shows the reduction effect produced by the high frequency oscillation shown in C. The rotation speed of the ball is as shown in Fig. 13E, in which the rotation of the ball does not rise in the time of the tangential force reduction due to the oscillation of the ball striking face. This effect can be determined based on the critical peak acceleration of the ball striking surface during the oscillation period. A key element in reducing friction is that the ball striking surface (the club's ball striking face) must intermittently interrupt contact with the ball that is struck. In order for this effect to occur when the ball hits the ball striking face, the acceleration of the ball striking face away from the ball must be large enough to interrupt the contact. In fact, the hitting surface must be removed from below the ball. This only needs to occur at the moment of the impact motion to affect the friction between the ball and the ball striking face, as shown in Figure 13. Since there is a very high preload during the impact of the ball with the ball striking face, there is an extremely high compressive load between the ball and the head as shown in Figure 13A. The normal load between the ball and the ball striking surface will accelerate the ball in the direction in which it eventually flies. The ball is stationary at the beginning and then it must withstand an extremely high acceleration after the impact motion to reach its peak speed. In order to interrupt the contact, the ball striking face must be accelerated at a level equivalent to the acceleration of the ball for at least a portion of this cycle.

The ball striking face must be moved backwards away from the ball to a sufficient acceleration to interrupt the contact. The amplitude of the oscillating motion of the ball striking surface multiplied by the square of the oscillating motion frequency is proportional to the peak surface acceleration. We have found that surface oscillating motion with amplitudes in the range of 5-20 microns and frequencies in the range of 50-120+KHz can generate sufficient surface acceleration to interrupt contact between the ball striking face and the ball under a wide range of impact conditions. If the oscillation occurs at a higher frequency (all other conditions are the same), a lower surface motion amplitude is required.

When this happens, the ball striking face and the high acceleration speed move backwards away from the ball in a very short time. Its principle of action is that the induced surface motion has a large enough amplitude and a high enough frequency, and the surface acceleration is high enough to overcome the compressive load caused by the impact of the ball and actually interrupt the contact between the ball and the ball striking surface. . The ball striking face will actually move away from the surface of the ball at a faster rate than the ball can react to the drop in interface force. It will move away from the bottom of the ball.

The interruption of contact is reformed for use in a micro-sliding area in a common interfacial friction model. In this friction model (Katoh) as shown in Fig. 20, a small amount of relative tangential motion (u) is allowed between the two objects (surfaces) before the frictional force rises to a level related to Coulomb (sliding) friction. Figure 20 is a simplified diagram of the effective coefficient of friction (tangential coefficient) (ft) as a function of the relative displacement (u) between two objects. This area where the coefficient of friction decreases is due to the tangential elasticity of the contact surface. Due to the relative sliding of the two surfaces relative to one another, the friction will rapidly increase (in the moving distance of only a few microns, indicated by u1 in Figure 20) to the asymptotic level associated with Coulomb friction between the two sliding surfaces. This friction model exhibits a micro-deformation that occurs before the contact surface begins to rub to tolerate relative motion between the two surfaces. This friction model is taken from the reference of Adachi.

By repeatedly interrupting the contact between the ball and the ball striking face before the two objects have sufficient relative motion in the asymptotic region, the sliding between the two surfaces will only occur in a micro-sliding region with a lower effective friction coefficient. in. Through multiple mid-contact cycles, the sliding motion is thus incorporated into the lower average coefficient of friction between the ball and the ball striking face.

Some dynamic interaction occurs between the ball and the impact surface. These forces can be considered to be effectively orthogonal to the ball striking face and tangent to the ball striking face. The normal force acts through the center of mass of the ball and preferentially accelerates the ball without directly triggering the rotation. The effect of the tangential force generated by the friction between the ball and the ball striking surface affects the tangential component of the velocity and the rotation of the ball.

In the tangential direction during the impact motion, the ball begins to slide on the ball striking surface as it begins to roll. Before the ball leaves the face, it usually rolls on the face with a slight sliding force, that is, the ball rolls (rotates) at a speed so that the contact point on the ball surface with the ball face does not occur relative to the ball. The movement of the surface contact points. By controlling the effective friction coefficient between the ball and the ball striking face, the degree of rotation of the ball in the impact can be controlled, as shown by curve E in FIG. If the friction is reduced enough, the tangential force will not be sufficient to rotate the ball to a point where it is simply rolling. Therefore, since the tangential (friction) force directly affects the rotation of the rotation, controlling these forces can control the rotation of the ball.

System production

The system is designed to capture the energy generated by the impact of the ball with the club head and use it to excite the high frequency (ultrasonic) vibration of the ball striking face, and use these vibrations to control the ball striking face and the ball as described above. Friction. It is fabricated using a piezoelectric element that is elastically coupled to the deformation of the ball striking surface. In the specific case of preference, the same piezoelectric signal converter (in the usual sense, the piezoelectric element as described above) is used to extract the energy generated by the impact to supply power to the system and utilize the obtained electrical energy. Ultrasonic vibration occurs on the club face. In the action, the impact will deform the club face, and the piezoelectric signal converter is elastically coupled with the ball striking surface, thus transforming the deformation of the ball striking surface into electrical energy (charge and voltage on the piezoelectric element). The quartz oscillator P10 or P11 in Fig. 10 is used. The electronic device coupled to the piezoelectric signal converter is designed to allow the piezoelectric element to be in an open state from the beginning when it is charged during the impact. At some point in time when the piezoelectric voltage reaches a predetermined threshold level (trigger level) in the system, at this point in time, a switch Q10 or Q11 in FIG. 10 is turned on, thereby connecting an inductor through the piezoelectric electrode. L10 or L11. The inductor is designed such that the resulting LRC electronic circuit (C is the capacitance of the piezoelectric element and L is the shunt inductor) responds to an oscillation that begins to pass through the electrode of the piezoelectric element to the inductor electronics. The value of the component force is specifically selected such that the frequency of the oscillation is approximately matched (as described below) to a high frequency dynamic structural mode of the ball striking face/piezoelectric system (such as the mode exhibited by the frequency response function in Fig. 22) - A high frequency ball striking motion/concussion is generated by a piezo motor/electrical connection. The system is designed to allow high frequency ball striking motion to be sufficient to control the friction between the ball and the ball striking face as described above.

Now we will discuss some of the system design issues in the system. The system is designed to maximize charging of the piezoelectric element to maximize electrical energy stored in the piezoelectric capacitor before ringing/shocking begins. This allows the oscillation to reach its maximum amplitude. In addition to this, the system is also structurally and electrically designed to maximize the correlation of the piezoelectric element with high frequency ball striking motion as will be described later.

The piezoelectric element (21) shown in Figures 2a and 2b is elastically coupled to the high frequency ball striking face mode to excite high frequency vibration. The circuit is designed to capture the impact energy and use it to drive an oscillator that substantially matches the selected semaphore's modal frequency. The electronic device converts a small amount of impact energy into a high frequency oscillation of the club's face. When the piezoelectric element starts charging, when it reaches a limit value (trigger level), the control switch (Q10 and Q11 in Fig. 10 and Q3 in Fig. 11) is turned on by the previously disconnected piezoelectric element to be shunted to The inductor initiates a high frequency oscillation at a frequency determined by the inductor and piezoelectric capacitor as shown in FIG.

The frequency is determined by an LC time constant. The inductor is sized to produce high frequency resonance and should have very low resistance to reduce energy loss, as well as a suitable core or core to reduce hysteresis losses and magnetic field saturation effects. The switch can be fabricated simply as a MOSFET transistor, although other switches may have fast turn-on time (second microseconds) and low turn-on resistance. We will discuss most of the other required features of the switch later.

Design of the ball striking face and the piezoelectric element

The movement of the piezoelectric signal transducer with the ball striking surface causes the deformation of the ball striking surface to generate piezoelectric voltage and charge. The goal of the design is to maximize the simultaneous connection of the piezoelectric signal transducer to achieve two effects: 1) maximizing the connection (and resulting voltage) with the deformation caused by the ball striking the ball striking surface - including hitting the ball The impact of the center of the face and the eccentric impact, and 2) the maximum connection with the high frequency mode of the connected piezoelectric element / ball striking structure system. The connection between the ball striking surface load and the piezoelectric open circuit (OC) voltage is represented by Figure 21, which shows a transfer function from a scattered load representing the impact of the ball to a piezoelectric open circuit voltage. This curve shows a response to the center shot, and there is also a hitting position on each square direction (upper = north, lower = south, front end = west, tail end = east) separated by 0.5 in. from the center position. Curve representation. A virtual static open circuit voltage of 10,000 N load commensurate with the head swing speed of 95 MPH is represented in Figure 21 by a lower frequency transfer function asymptote. This sensitivity value (FOM) can be averaged over a series of hitting positions to arrive at a design FOM that attempts to maximize the piezoelectric voltage generated by a series of center and eccentric shots.

The connection to the mechanical oscillation of the high-frequency ball striking surface is represented by the transfer function in Fig. 22. This graph represents a transfer function that changes from the applied sinusoidal piezoelectric voltage to the surface of the ball striking surface at the center of the ball striking face (and the points that are 0.5 inches apart in each of the directions described above). A series of motion/accelerations at the ball striking position can also be used as a sensitive value for the design - average or weighted in a manner similar to the voltage response transfer function of Figure 22 described above. As you can see, the high-frequency acceleration response is maximized when the ball striking face and a connected vibration mode of the connected piezoelectric system ("excitation mode" in Figure 22). In the specific case of preference, this modality will occur at 127 KHz. At this frequency, hitting the ball striking surface will achieve the maximum surface acceleration. In a similar manner, a piezoelectric oscillator ringing in the frequency range associated with a high acceleration response will produce the largest second plane acceleration.

Our design goal is to maximize the open circuit voltage achieved by center or eccentric hitting and to maximize surface acceleration during subsequent ringing responses generated by this voltage after the circuit is triggered. The geometric design of the system is also specifically designed to maximize these two sensitive values to produce the largest (due to system startup) surface high frequency response.

The piezoelectric element, the club face, and the tapered housing member, which will be described below, are all designed to allow the connected system to exhibit these qualities. This is a related system design, because the voltage generated by the surface reacting to the impact is a function of the housing, the piezoelectric signal converter, and the material of the ball striking surface. In addition, the shape and frequency of the high frequency mode is a function of all three of these design elements. In the following sections, the piezoelectric signal converter will be described along with the structure of the housing and the ball striking face.

Stacking and end cap design

The piezoelectric element is shown in the exploded view of the ball striking face assembly in Fig. 18 and the sectional view of the striking face subassembly in Fig. 19. The piezoelectric stack itself is represented by the piezoelectric element 21, and the actuator assembly including the piezoelectric element (stack) 21, the wire 22, the stacked end cap (end piece 23), and the strain relief ring 25 is collectively shown in FIG. The subassembly (piezoelectric end cap assembly 15) is indicated. The preferred design of the piezoelectric element (actuator) 21 is a multilayer stacked type 3-3 type actuator. It can also be a single rod, tube, or rod that allows the electrical input to be used to create axial actuation (motion and stress) and (opposite) to cause axial loads to generate voltage and charge on the component. Please note that 1-3 (horizontal) connected tubes or systems also have this effect but using 3-3 stacking produces minimal voltage because each layer can be very thin, while the 3-3 modal multilayer stack uses The 3-3 mode associated with the high voltage electrical connection coefficient. A centrally located piezoelectric stack is placed between the ball striking face 10 and the backing plate (end cap 13) which is structurally coupled to the ball striking face at a carefully determined position. The piezoelectric stack has a convex end piece 23 to create a point contact with the ball striking surface to reduce bending moments due to eccentric settings stacked in the system. This is very important in this high stress system because it is best to operate the piezoelectric element close to the maximum allowable stress to reduce the weight of the system and create a maximum electromechanical connection. In addition, the convex surface 26 of the end cap (end piece 23) is designed to provide more uniform stress dispersion through the stack to create a more desirable stacking action and reduce stress unevenness in the stack that may cause breakage or damage to the stack under impact. The thickness of the end caps is specially considered to ensure adequate homogeneity. In a preferred case, the rounded end of the end cap has a curvature radius of 12.5 mm and the contact surface from the tip to the piezoelectric stack has a dimension of 3 mm. These end caps are made of a rigid material such as aluminum or steel to more efficiently distribute stress onto the stack and reduce the thickness/quality of the part. They can also be made by laminating these materials to facilitate manufacturing.

The piezoelectric element 21 is composed of overlapping multilayer piezoelectric elements each having a thickness in the range of 15 to 150 μm. Systems employing thinner laminates 24 have higher capacitance and therefore do not require induction to achieve the desired frequency than systems using thicker laminates. For example, a 9mm diameter circular stack has a total length of (d1) 1 cm, if stacked with a 90 micron stack, the stacked capacitance = 550 nF; if at 35 microns, the stacked capacitance = 3442 nF.

Conversely, stacks with thinner stacks also have higher currents when triggered, while higher currents can cause excessive losses. A thinner laminate will also lower the voltage of the system under the same stress, which simplifies and reduces the design of the electronic device. A specific example of preference uses a 90-100 micron thick laminate. Piezoelectric material is a "hard" composition similar to the typical PZT-4. We specifically chose it to reduce the voltage hysteresis loss and increase the toughness of the stack and the resistance to high axial stresses during impact. The wires are arranged in such a way that all of the piezoelectric stacks act in parallel. The wires are mounted on one side of the stack as shown in Figure 18. The piezoelectric element has a length of ~1 cm and a diameter of 9 mm. It is secured to the end caps that are curved and extremely thin with a strong epoxy (to maximize the bond). The overall piezo end cap assembly 15 has a length of ~16 mm.

Batting surface and core design

The goal is to have a good correlation with the deformation of the ball striking surface in the impact in order to generate the maximum voltage and charge (generated electrical energy) in the impact while at the same time being in good contact with the high frequency mode of the ball striking face system that can be excited by the high frequency oscillation of the actuator. The system converts the impact energy into a high frequency oscillation of the ball striking face. The high frequency ball striking surface oscillation can be used to control the frictional contact between the ball and the ball striking face by reducing the friction of the contact surface with surface vibration.

The ball striking face is constructed of carefully controlled thickness titanium to form the desired modal structure with a high frequency mode that can be simply excited by the piezoelectric element. The overall arrangement of the ball striking face, the housing, and the piezoelectric element (collectively referred to as the ball striking face assembly 14) is shown in the assembled view of Fig. 17, the exploded view of Fig. 18, and the cross-sectional view of Fig. 19. It comprises a piezoelectric element 21 and an end piece 23 (as described above) mounted on the ball striking face 10 and subjected to a load from the ball striking face through a conical housing 12 structure. The piezoelectric element engages the ball striking face at the impact center point 33. The ball striking face is provided with a recess 33 having a slightly larger radius of curvature than the end cap (about 13 mm) to provide a correct mounting position for the stack on the ball striking face.

A tapered housing 12 (having a freely selectable independent end cap 13) engages the distal end of the piezoelectric end cap assembly 15 (the opposite end of the ball striking face). It also has a curved contact surface to provide a correct mounting position for the piezoelectric element end cap. The threaded end 29 of the tapered end cap can be locked to the threaded ring 37 on the ball striking face 10 (inside surface) as shown. By locking the core on the ball striking face, the piezoelectric element can be mechanically coupled to the ball striking face, and the axial dimension change of the piezo element can be associated with the bending of the ball striking face. The radius of the ring 56 and the thickness and geometry of the tapered housing are carefully determined to reduce the elastic loss and deformation between the ball striking face and the distal end of the piezoelectric element. The housing must have as high an axial rigidity as possible to maximize the correlation between the piezoelectric action and the deformation of the ball striking face.

The tapered housing can be provided with manholes on both sides, as shown at 32 in FIG. These holes facilitate stack positioning and connect the leads to electronic devices located elsewhere in the club head. Care must be taken in the design of the ball striking face, the tapered casing, and the piezoelectric element to avoid reaching critical stress levels on these components under repeated high impact loads. The system is designed to lock the housing to the ball striking face to positively press the piezoelectric stack against the ball striking face and provide a high compressive preload to the piezoelectric element. Its goal is to keep the actuating element in compression during impact and action because the piezoelectric element does not have high tensile strength.

The ball striking face has a thickness of 2.4 mm on the inner side of the core ring 39 and 2.7 mm on the outer side of the ring 34 and transitions to a minimum thickness of 2.2 mm with a step difference 35 and a bevel 53 , 36 (the outwardly enlarged radius constitutes a ring shape) . The greater thickness outside the ring is due to the fact that the stiffer tapered shells tend to have a higher thickness, so thicker wall thicknesses must be present at these locations. The threaded ring can be welded to the ball striking face or formed integrally with the ball striking face, which is approximately 2 mm thick and 3.5 mm high (38 in the figure). The tapered housing 12 has a wall thickness of approximately 1 mm.

One of the important dimensions is the diameter of the housing on the ball striking face mounting ring 38. This diameter should be as large as possible but must allow the system to have a clear axisymmetric vibration mode at a high enough frequency to be able to excite high accelerations on the ball striking surface structure. In the particular case of preference, the ring 38 has a diameter of approximately 35 mm and a height of approximately 4 mm. The thickness of the ball striking face 39 in the ring is 2.4 mm, which allows one of its resistive modes (as if it were a circular plate that is independent of the piezoelectric element and vibrates independently) and the piezoelectric element The first axial extension mode is matched. The engagement of the ball striking face/piezoelectric element mode can form a coupled system (after the piezoelectric element is mounted on the ball striking face), which can have a very high modal amplitude at the set frequency.

The tapered housing 12 may be provided with a threaded end cap 13 at its distal end, the threaded surface 30 of the housing mating with the threaded surface 27 of the end cap. The opening in the housing 12 facilitates the assembly process. Due to the detachable end cap design, the tapered housing 12 can be first mounted to the ball striking face, and then the piezoelectric element can be inserted and the end cap 13 can be locked to the conical housing 12 to pre-tighten the piezoelectric element. Press on the hitting surface. The end cap can be designed as a convex curved surface to engage the curved end cap of the piezoelectric element. The end cap 13 can have a threaded surface 27 for securing it to the tapered housing 12. The end cap 13 and the housing 12 each have a hex nut 28, 31.

Circuit component

The entire system is a system for electrical energy conversion - this electrical energy is generated in a "virtual static" manner in the impact through an elastic connection between the piezoelectric element (which is subjected to load during impact). Since the stress/load is applied to the piezoelectric element, the voltage on the piezoelectric element and the stored electrical energy increase. The electronic device (shown in Figures 10 and 11) converts the electrical energy stored on the piezoelectric element into a high frequency oscillating motion on the piezoelectric element. To achieve such a conversion, it will have an "on/off motion" to turn on an inductor (L1 in Figure 11 and L10 or L11 in Figure 10) to turn on the charged voltage when a predetermined voltage limit is reached. The electrode of the electrical component. The voltage level can be pre-set to match an impact of a specific amplitude or intensity, so the system is triggered only under a strong enough impact motion to ensure that the rotation of the ball can be corrected.

The switch can also be triggered by events other than the threshold voltage level. For example, a peak detection circuit component that activates when the piezoelectric voltage begins to fall from its previous value can be utilized to allow the trigger to occur at the peak of the load during the impact (peak detection circuit).

The size of the inductor allows the capacitor and inductor to oscillate at a pre-set frequency (eg 120 KHz). Piezoelectric capacitors are approximately 480nF-600 nF (based on stacks with a stack thickness of 100 microns, a diameter of 9 mm, and a total length of 1 cm). In this system, the ideal inductors L10, L11, and L1 have values of ~1-10 microHenries.

Simply put, a circuit design based on a high level of function should be such that it senses the voltage level on the piezoelectric element when the piezoelectric electrode is open and then turns it on at a predetermined voltage level. An inductor is connected to a switch of the circuit, whereby the piezoelectric element (which already has a voltage before the trigger) oscillates at a high frequency equal to the voltage and is charged by the inductor that generates the ringing when the piezoelectric element is discharged. , as shown in Figure 12.

The circuit depicted in Figures 10 and 11 has this simple function of a trigger switch. Since the signal converter (piezoelectric element) is pressed during the impact, the charge and voltage on its electrodes rise to begin storing the impact mechanical energy that has been converted to electrical energy by the signal converter. The specific circuit action causes it to turn on a switch to connect the capacitive piezoelectric element to the inductor when the voltage reaches a critical threshold. The size of the inductor allows the LC time constant (electrical resonant frequency) of the connected circuit to be very close to the resonant frequency of a structural mode - in this case the selected ball striking mode.

High frequency ringing must be as efficient as possible when converting "virtual static" energy in piezoelectric capacitors into oscillatory energy. This would require a very low loss oscillation, resulting in a very low damping ratio and a very high quality factor (usually less than 10% of critical straightness, preferably less than 5% of critical straightness). Because of this, it also requires "turning on" very low-resistance switches and very low-loss or lossless components, such as low-loss inductors and no resistors in the main connection path.

The high performance of the system also means that any parasitic losses can be avoided. A typical parasitic loss is the driving of a switch control circuit or any electrical system component due to the need for charging, such as a capacitor that reduces the open circuit voltage that the piezoelectric element would normally generate upon impact.

The typical voltage expected on a piezo element to be seen before triggering is approximately 400v (the system may experience voltages from 100v to 600v). Some of these components will be high voltage components and therefore must have a high breakdown voltage, but at the same time must have a very low turn-on resistance to achieve lower losses.

Therefore, there are usually four components: 1) a piezoelectric element 21 having a certain capacitance, 2) a switch Q3 in Fig. 11, 3) a control circuit for controlling the switch, and a switch for turning on the switch. The 4) inductor (the L1 in Fig. 11) that connects the piezoelectric electrodes.

It is very important that this main switch must be turned on very quickly when the voltage on the electrode of the piezo element reaches a critical level (predetermined threshold level). The quick turn-on of this switch is extremely important to reduce losses, because if it is turned on at a relatively slow speed at 120 kHz (if it takes a few microseconds to turn on), before the actual ringing can occur, the voltage The loss of electrical voltage can be considerable. Essentially, the piezoelectric charge will be depleted before it is fully connected to the inductor. This will severely limit the initial and subsequent voltages of the oscillation. An ideal electronic circuit connects the inductor to the piezoelectric element with very little voltage drop or even no voltage drop (compared to the original open state) (before starting the turn-on). In simple terms, during operation, the system will reach a trigger threshold level and then quickly turn on a high voltage switch with minimal loss and ringing at the level of the open circuit voltage determined by the trigger event.

A block diagram of the electronic circuit is shown in Figures 10a and b, which shows that the control circuit drives a switch to connect the inductor element to each terminal of the piezoelectric element. Figure 10a shows a configuration in which the switch is between the piezoelectric element and the inductor (high side), while Figure 10b shows a configuration in which the switch drain normally communicates with ground (low side). The detailed circuit of the configuration of Figure 10b is shown in Figure 11. In the next section, we will refer to the component numbers in this figure to illustrate its role. The main circuit components function as follows:

Piezoelectric element (P1):

The circuit is connected to a piezoelectric device P1 which is connected to the inductor L1 (Fig. 11). In Fig. 11, the piezoelectric element can be represented by a voltage source connected in series with the representative capacitor C. In fact, these components are not part of the circuit, but are used to represent the piezoelectric components for ease of understanding. Such a representation omits the connection between electrical energy and mechanical energy, and actually only reflects the effect of mechanical forces acting on the piezoelectric element (mechanical and electrical connections). The size of the capacitor C reflects the breaking capacitance of the piezoelectricity; and the magnitude of the voltage source can represent the open circuit voltage that occurs when the piezoelectric force acts in the open state (without any contact). A more complete piezoelectric model would include electricity that simulates mechanical properties such as the stiffness and inertia of the piezoelectric device, as well as a transformer or phaser used to contact the mechanical and electrical fields.

Inductor (L1):

The inductor L1 is connected to the piezoelectric element P1. Since switch Q3 is open, it is floating at the beginning (not connected to ground), so no current flows through it. When the trigger event occurs and the main switch (Q3) is subsequently turned on, the floating side of L1 is connected to ground and a closed electronic circuit is formed between the piezoelectric element and the inductor - now connected in parallel with the piezoelectric capacitor. This creates a closed LRC electronic circuit in which the piezoelectric element acts as a capacitor, L1 acts as an inductor, and the series resistance of L1 and any resistance of the main switch Q3 (and any wire resistance) acts as a resistor R. . The basic goal of this design is to create a highly resonant circuit (low R and low damping) to provide a good connection between the piezoelectric component and the electrical shock and mechanical oscillation of the ball striking face. For this reason, the inductor must have a very low series resistance at the oscillation frequency of the LRC electronic circuit. This frequency is typically in the range of 50-200 kHz. High quality, low loss inductors specified for high frequency operation (such as when power is turned on/off) must be used. In our system, the piezoelectric capacitor is about 200-600 nF (~400nF is more typical), and the inductance value in the range of 1-12 μH is usually used to set the oscillation frequency (~6 μH is more typical), as in the formula. =1/sqrt(LC), where f is the desired electrical resonant frequency (this formula applies to some systems with slight damping). In our system, we chose to use 3.3 μH power choke coil IHLP5050FDRZ3R3M1 from Vishay or Panasonic's replacement coil PCC-F126F (N6), which has a ~11 mΩ DC resistance at 8.2 μH (and extremely Sophisticated volume). All compromises must be made between low resistance and size. Both weights are approximately 3 grams. Since the inductance value is typically a function of frequency, an inductor having the correct value at the frequency of the resonant circuit must be selected.

The saturation effect may be important for on/off (because the current can be very large), so care must be taken to select an inductor that will not saturate the core. Saturation changes the effective tuning and inductance values and complicates the tuning process. At high current levels, the magnetic field in the coil saturates, effectively reducing the inductance of the coil. This can make it difficult to tune the resonance (now amplitude-predicted) and cause excessive losses on/off, because the lower inductance of a saturated inductor does not produce effective current resistance to limit the high current during on/off. Therefore, it is best to choose an inductor that reduces the nonlinear effects on complex tuning, such as core saturation and hysteresis losses.

Main switch (Q3):

The main switch is one of the most important components in an electronic circuit. When a predetermined threshold voltage is reached, the control circuit raises the gate voltage of the N-channel MOSFET (metal oxide field effect transistor) to turn on the MOSFET (Q3). Above a critical gate voltage (~5-10 V), the "on" resistance of the MOSFET drops significantly. The MOSFET changes from an open state to a low open resistance connection to the inductor ground. The size of the resistor R4 allows the gate to be normally grounded even in the presence of a leakage charge current from the MOSFET (Q2). When the control electronics are energized, the gate of Q3 will rise rapidly to the threshold voltage and the "on" resistance of Q3 will drop rapidly, essentially turning the switch on. Since the charge required to energize the switch comes from the piezoelectric element itself, this energized charge is completely parasitic and should be minimized to maximize the initial piezoelectric voltage level. To achieve this, one of the main requirements of this MOSFET is the extremely low gate drive charge and the very low total gate capacitance. This MOSFET also requires very high source-to-on-voltage operation - that is, it can support the piezoelectric voltage without crashing before the trigger condition is reached and power is applied. A higher breakdown voltage is therefore very important. A lower turn-on resistance (typically less than 0.1 Ohms) is also important because it contributes to shock absorption in electrical shock and (perhaps) contributes to the main power loss mechanism in the system. It is also important to note that these MOSFETs have an intrinsic diode from source to drain. This provides an opposite current path during the electrical oscillation rise after on/off. At the current current, switch Q3 is held open by diode D3 during electrical oscillations, which allows charge to flow to the gate when energized and does not exit the gate during subsequent voltage swings during oscillation. The time constant for how long Q3 remains on after power-on is determined by the gate capacitance and resistor R4. After power-on, the charge will begin to leak slowly away from the gate until it passes the voltage limit, dramatically increasing the source resistance and effectively opening the switch.

We have taken and evaluated a variety of high voltage MOSFETs and currently have two benchmarks, the APT30M75 from Advanced Power Technologies and the SI4490 from Vishay Siliconex. Their characteristics are compared as follows:

These are selected based on their lower gate charge and lower "on" resistance while still having high voltage capability. However, in the case of very high voltage systems, the preferred switch is the STY60NM50 from ST Microelectronics, which is rated at 500 V and 60 A.

Control circuit:

The control circuit is designed to rapidly increase the voltage across the Q3 gate when the piezoelectric element reaches a threshold voltage level. It must be able to turn on quickly (and control the electronic circuit to have a high gain) to avoid high energy losses during the transition to the on state - transitioning too slowly can limit the peak negative voltage of the electronic circuit and subsequent ringing.

Another feature of the control electronics is that it latches, which means that when Q3 is turned on it will remain on regardless of the voltage of the piezoelectric element. It will remain on for a period of time determined by the leakage of charge through the Q3 gate of R4. R4 is typically 3 megaOhms.

The function of the control electronics is as follows: Q3 is initially turned off, so the voltage at the source terminal (top) of Q3 is essentially the open circuit voltage of the piezoelectric element. The current begins at a threshold voltage determined by Zener diodes D4, D5, and D6, which collectively begin to conduct conduction at the combined voltage rating (plus the voltage drop across diode D1). Capacitor C3 is charged and transistor Q1 is turned on via D4-D6 pass. It is very important that D4-D6 must have very low leakage because the micro-premature leakage via D4-D6 may charge capacitor C3 to turn Q1 partially or prematurely. The size of R2 (typically 100 kOhm) limits the voltage rise associated with the leakage current of Zener (D4-D6) and forms a discharge path for capacitor C3 (between two strikes). Transistor Q1 only needs to be specified for low voltage because its source is connected to control supply capacitor C4, which is maintained at a level of no higher than 28 V by Zener D2.

The control supply capacitor C4 is charged in the initial high voltage ride of the piezoelectric element. It is charged at a fixed value determined by resistor R3 (typically 5 kΩs). In this system, we set it to about 5kΩs, and the charging time is about 100-200 μsec in the range of C4 of 47 nF. In design, the size of the resistor R3 can be quickly charged according to the size of the capacitor C4. Capacitor C4 is sized to allow its charge to dump to the uncharged Q3 gate, lower the voltage on C4 The gate voltage is fully turned on. Therefore, the size of C4 must be large enough to supply Q3 with enough gate charge level to achieve the turn-on. Since the charge on C4 is parasitic on the piezoelectric charge and effectively reduces the piezoelectric voltage, C4 is preferably as small as possible but still causes the required gate voltage rise on Q3. This value may be as low as 3.3 nF for the selected M1, but may require 47nF for some larger main MOSFETs. In fact, the peak voltage setting of capacitor C4, limited by Zener diode D2, should be as high as possible within the feasible range while still maintaining the control MOSFET and transistor at a low cost and low loss level. In our electronic circuit, we chose to supply capacitor C4 with 28 V. Tests have shown that under the various values of these components, the control electronics only reduces the piezoelectric voltage by a fraction of the total open-circuit piezoelectric voltage.

When the threshold voltage is reached and switch Q1 is turned on, this will then "crush" the gate of the P-channel MOSFET (Q2) to turn it on quickly and connect the charged capacitor C4 to the gate of the main MOSFET Q3. This will then charge the gate of Q3 and quickly turn on Q3. There is a Fairchild BSS110 for the P-channel MOSFET (Q2); this MOSFET version has a lower leakage between the gates from C4 to Q3. This leakage will occur when C4 is charged but switches Q2 and Q3 are still normally disconnected. The leakage charge on this Q3 gate will cause Q3 to open partially prematurely. Using the MOSFET in Q2 eliminates this leakage and achieves a clear on/off action. Once the gate of Q3 is charged, it remains charged because it is charged through diode D3 and will only be re-disconnected after the gate charge is released via R4.

Overview of Electrical Conclusions: Intrinsically (and at the beginning) charging of a piezoelectric element in an open state. When the extremely low parasitic losses cause the piezoelectric voltage to drop to a user-controlled threshold level, an electrical switch connects an inductor to turn the piezoelectric element on and cause it to start oscillating at a very high frequency. This switch must be turned on very quickly to avoid excessive losses in the transition from the open circuit to the electronic circuit. It must have a very low turn-on resistance and must have a circuit that can activate this switch and power it without capacitive current consumption because the capacitive current consumption reduces the voltage on the piezoelectric element. The power used to turn the switch on is different from the power used to oscillate.

It preferably has the ability to tune, cut or cut under electrical control, and change the inductor to provide a variable tuning frequency.

Some electronic circuits have an auto-locking oscillation. They automatically fall into an oscillating frequency that is determined by the feedback gain or delay gain in the electronic circuit. This will allow the vibration of the piezoelectric element to be locked.

We have proven that it would be useful if the system had some external interface that could detect voltages and signals in the system during its action. Various wires/sensors/probes (from the external interface of the board) allow us to adjust and detect the status and condition of the system throughout the test and operation. The signal can be transmitted through an external cable that does not interfere with the system, or can be sent wirelessly. Contact with external electronics (wired or wireless) can also be used for monitoring/telemetry and can be used to reprogram system performance or to perform diagnostics and data downloads.

These circuit components (in addition to the piezoelectric element being bonded to the ball striking face) may be arranged on one or more sides in a single or multiple circuit board form. Preferably, the circuit board is disposed within the head of the golf club or outside the club and is connected to the circuit board by a signal converter wire from the head, as shown in FIGS. 13 and 14. Some or all of the components can be placed on an external circuit board to facilitate access to circuit components to change trigger levels or to make adjustments to other circuits. Alternatively, the circuit board 18 can be attached to a base plate 54 (or other detachable component) as part of the base plate assembly 16 (shown in Figures 14 and 15 for attachment to the club head, and Figures 16a and 16b are shown in Figures 16a and 16b). Removed from the club head, wherein Figure 16b shows the interior 42) of the club head body. The base plate assembly 16 can be designed with a wire 22 or plug connector 20 designed to provide an electrical connection between the detachable component portion and the main club body. Such a design is shown in the cross-sectional views of Figures 14 and 15 and Figures 16a and 16b (the bottom plate assembly is removed). These figures all show that a circuit board 18 is mounted on a detachable bottom plate 54 through a fixing post 45 so that it can be mounted on the base plate and fixed to the head body 11 by the fixing post 47, which can be on the main circuit board. An upper joint 49 is electrically connected to a joint 20 fixed to the second "connector" connecting plate 19 of the head body 11 through the fixing post 46, and is connected to the piezoelectric element 21 and the striking surface. Assembly 14 forms an electrical connection. The club and the head body 10 are connected by a collar 40.

This design makes it easy to remove and adjust/maintain/repair circuits and boards. The connector and connector board are secured within the head to facilitate removal of the main circuit board. Additional connectors can be configured on the main board to allow for external monitoring/diagnosis during swings and impacts. In addition, this information can also be wirelessly transmitted to a receiver and stored for subsequent testing. Or the data obtained during the impact movement can also be stored in the on-board memory on the board, and then can be dumped/downloaded by the command prompt. Telemetry transmission can be done over a wireless or wired path. These information that can be stored and monitored includes the speed of the strike, the impact force, the impact position and strength of the ball on the ball striking face, the deceleration of the club head and the resulting acceleration of the ball, or any dynamics and conditions that may be related to the swing and impact. The relevant system state (or the result of the reaction of the ball with the club head system vibrates).

Assembly procedure

When assembled, the order of each action can be performed in the order shown below.

1) The ball striking face 10 is formed by a suitably arranged ring. A post-forging work is performed to set the inner diameter of the ring and the thread 37 on the inner diameter of the ring. At the same time, the processing and polishing of the dimples 33 are performed at the positions where the joining will occur when the stacking is in contact with the ball striking surface.

2) A dummy screw member is inserted into the thread of the face of the ball striking face to fix its shape and then the ball striking face is welded to the head body 11. Then remove the dummy screw that supports the shape.

3) Lock the tapered housing 12 until it is locked.

4) The piezoelectric end cap assembly 15 is loaded into the core so that it comes into contact with the ball striking face. Before the end cap of the core can be locked and thus the piezoelectric element can be pre-locked against the ball striking face and locked in the correct position, a support made of plastic or other soft material can be attached The piezoelectric element is held in the correct place/position. The wire 22 of the piezoelectric element must be led through a hole 32 in the wall of the housing. This hole 32 should be fitted with a suitable grommet or strain relief ring 25 to avoid wire friction during the motion induced by the impact.

5) The end cap 13 is then locked to the magnetic core (the curved side is joined to the piezoelectric stack assembly) and locked until the piezoelectric element does fall into position and can be used to facilitate interruption of the ball striking face and the piezoelectric end in the impact. The proper preload of the contact between the covers against the ball striking face (approximately 1000 N compression preload). A thin layer of oil can be applied between the end cap of the piezoelectric component and the ball striking face and the core end cap to help fall into position.

6) Next, lock the screws on the core end cap 13 with a set screw, epoxy, or other fixing method.

7) Next, the wires of the piezoelectric element are soldered to a small connecting plate 19 for fixing the joint 20 to engage the main (detachable) circuit board 18. The connecting plate is permanently fixed to a fixing post 44 in the head with epoxy or screws. The connector board should be positioned so that it can engage the main board without any interference.

8) The core of the club head 43 is adhered to the head body 11 by an epoxy bonding operation of 160 degrees C.

9) Mount the main circuit board 18 and the connector 49 to the detachable base plate 54. The entire detachable assembly 17 is then loaded into the club head and screwed. The system is now ready to use.

Alternative case: the ball surface rigid control

In the previous sections, we describe a method and system for using the ultrasonic vibration to control the friction between the ball striking surface and the ball. In this section, we will describe an alternative to rigid control using a piezoelectric (or other type) signal converter coupled to the ball striking surface of a golf club (push, 1 wood, iron). case. By changing the effective stiffness of the ball striking face, we can influence/control the impact process and results between the ball and the ball striking face, which is a general example of an impact control system using solid state signal converter materials. The concepts presented in this section will be described by a piezoelectric transducer connected to the ball striking face, but a more appropriate statement would be a system containing any signal converter coupled to the ball striking motion - as long as this signal The converter has the ability to convert mechanical energy into electrical energy and vice versa (ie, to make an electromechanical connection).

General principle

Its general concept is to use a mechanical link as described above to allow a signal converter coupled to the ball striking face to change the effective stiffness of the ball striking face under specified conditions. Basically, we can control the stiffness of the ball striking face (with precisely controlled stiffness) to create a desired effect on the ball's impact with the ball striking face. The stiffness of the ball striking face can be controlled because in a system with electromechanical connections, changing the boundary conditions on the electrical side of the system changes the effective stiffness of the mechanical side of the system. For example, we all know that the stiffness of a shorted piezoelectric element is lower than the corresponding stiffness of an identical piezoelectric element when the electrode is open. This effect can be used to change the effective stiffness of the piezoelectric material and the piezoelectric element (longitudinal stiffness in the polar or shear mode or lateral stiffness in the polar direction). Since the piezoelectric element is mechanically coupled to the ball striking face, the change in rigidity of the piezoelectric element causes a change in the rigidity of the ball striking face.

In the case of the mechanical connection of any of the above-mentioned signal converters and the ball striking face (concepts 1-8), the signal converter is a machine that changes the behavior of the ball striking face by changing the rigidity of the signal converter. link. In the case of elastic joints (concepts 1-4), we can say that the change in the stiffness of the signal converter can directly change the stiffness of the ball striking surface when it hits the ball. This will equally change the deflection of the ball striking face during impact. In the case of inertial connections (concepts 5-8), the change in the stiffness of the signal converter causes a change in the connection between the ball striking motion and an inertial mass (which is part of the club head in Concept 8) - If it is not virtual static stiffness (DC), the dynamic stiffness of the ball striking face is changed. This is because the concept of these inertial connections is not a DC link. They have no effect on the system at very low frequencies because the inertial forces from the proof mass are minimal at low frequencies. However, they are designed to affect the system at each impact time scale, so in these concepts, the signal converter is rigid in the frequency range associated with the impact of the ball (approximately 0.5 microseconds and 1 kHz). The change will cause a change in the rigidity of the system. Therefore, any of the concepts 1-8 can be used to change the effective rigidity of the ball striking face by changing the rigidity of the signal converter during the impact.

Signal converter configuration

As mentioned above, any of the previously described signal converter configurations can be used as the basis for this impact control concept. For example, one example is to use the same way of connecting the piezoelectric stack to the ball striking face as Concept 2. In the mechanical design shown in concept 2 and the schematic diagrams of Figures 2a and 2b and the detailed drawings of Figures 13-19, the DC stiffness of the ball striking face from the short circuit to the open circuit (for orthogonal to the ball striking face) The center impact force) will increase by about 25%. Another configuration using a stacked signal converter is to use a planar (possibly packaged) piezoelectric signal converter (or other solid state signal converter material) to be attached to the ball striking surface and thereby extend and penetrate the ball striking surface. The curved joint is associated with the movement of the ball striking face. The bending stiffness of the ball striking face (and the overall stiffness of the impact force on the ball) can be changed by changing the boundary conditions (open or short) of the circuit.

System circuit function

To be able to control, the electrical boundary conditions of the signal converter must be determined (controlled) based on certain reactions or behaviors of the system. This can be determined by the signal converter itself (ie, the voltage or charge when it is under load) or can be determined by an independent sensor (such as the ball striking surface stress or the ball striking surface sensing sensor). An accelerometer can also be used to determine the deceleration of the club head during impact and to trigger the system accordingly.

When active, the signal converter is placed in an open or shorted state depending on the sensor. For example, electrical connections can be controlled based on impact strength - making the system stiffer in stronger impacts and less rigid in softer impacts. This may be especially important in situations where a more pronounced hitting feel, longer dwell time, and increased rotational thrust or tee angle (such as taps and putts, or tackles and short iron shots) are needed.

At the time of the tap, we all know that the focus is on reducing the gliding to give it as much rotational thrust as possible before the ball leaves the club's face, and to minimize the gliding distance of the ball before it begins to roll.

The impact of the putter will compress the front of the golf ball backwards in a moment while widening the "waist circumference" of the ball. The ball then bounces back to its original shape, causing it to move forward away from the club's face. A perfect situation is to allow the golf ball to bounce in a direction that is only determined by the direction in which the pusher moves and the angle of the putter's face with respect to that direction. Since the golf ball is not perfectly balanced, the imperfection of the ball itself may cause a deviation in the rebound direction (referred to as compression deviation). Reducing the amount by which the ball is compressed during impact can reduce compression bias. A softer hitting surface reduces the interface load and reduces ball compression. Therefore, if properly adjusted, the function of the system can reduce the compression deviation of the ball and achieve the best serve and rolling direction. For example, in the case of putters, the control of distance and direction can be improved by combining a relatively soft club face and a high rebound bounce.

The elastic deformation of the ball and the ball striking surface material has a very large influence on the direction, speed and manner of bounce from the club face when the golf ball is pushed, served, or compressed in the impact motion. The effective elastic force of the ball hitting the ball is the combination of the ball and the elastic force of the ball striking face. In order to improve control, in terms of putters and tackles, the best part of the effective spring force is from the club face, not from the ball compression to reduce compression bias.

Contrary to this, if you want the ball striking surface to be more obedient to improve control, tapping and short-distance hitting, the impact speed that can increase the control amount may be due to the impact strength and the striking force against the striking point. And it becomes less obedient to hit the ball surface. Impacts including deformation may cause ball ballistic trajectory errors and inconsistencies, especially in high-intensity, non-ideal impacts. Basically, an increase in obedience may result in loss of control in the event of a higher intensity impact.

Therefore, in order to improve shot control and reduce dissipation, the club face is preferably less rigid at lower impact strength but higher at higher impact strength.

In a specific case of preference, when the piezoelectric element is in a short-circuit condition and the time the ball is in contact with the club face is increased, the "residence time" is associated with the club face having a higher coefficient of friction. This can add a little control and optimize the results of the tee conditions.

Increasing the dwell time allows the club to have more chances to contact the ball to achieve the purpose of imparting rotational thrust. We can also say that a longer dwell time can improve the feel of hitting.

For example, when using a push rod for a lower speed impact, the shorted piezoelectric element allows the club's ball striking surface to "envelop" the ball when it comes into contact with the ball, which increases the dwell time and reduces the ball's glide on the grass. . In addition, this performance feature can also improve the sense of hitting and control, which is what we often say to improve accuracy, consistency, and confidence.

Conversely, a stiffer hitting surface in a higher speed impact can also improve accuracy and consistency by reducing errors caused by elastic deformation. In addition, the variable stiffness effect also means that the golf club can produce a distinct range of performance characteristics with a simple circuit change. In a passive golf club design, the same range of performance characteristics requires the use of multiple golf clubs with the same design but different club striking material boundary conditions to achieve this requirement. Therefore, the concept of a golf club system that can be electrically adjusted or adapted is very feasible. In this concept, changing a resistance or trigger level can be used to change the behavior of the club to meet the needs of a particular hitter or strike condition.

Under certain conditions, the impact of the impact can be controlled by making the system harder during the impact. In addition, the change in stiffness can also be set and determined by the user prior to hitting the ball, thereby allowing the club to achieve a certain degree of fit with the user. The user can select a most desirable rigid setting and can be set in the factory or user-controllable system, or can be based on the user's wishes or current conditions (weather, wind speed/wind direction, etc.) before playing. ) Perform a rigid setting. The switch or other electrical setting device can be placed in a convenient place for the user to use, for example, at the end of the grip.

A simplified diagram of a preferred example of using the piezoelectric element itself as an impact sensor can be seen in FIG.

In effect, the electronic circuit will open the electrodes of the piezoelectric primary electricity in the event of a hard impact, and short-circuit them in the case of a soft impact. The signal converter (connected to the ball striking face) is electrically connected to the charge or voltage sensing circuit. Basically it is designed to be used as a perceptron. The sensing circuit keeps the high wire of the piezo element grounded, essentially shorting the piezo element. In this case, the piezoelectric signal converter exhibits the mechanical characteristics of the short circuit. If the sensor output voltage reaches a critical level, the electronic circuit will be triggered and the switch that connects the piezoelectric element to the circuit (normally closed) will be disconnected, essentially the electrode of the piezoelectric signal converter. Open circuit. After the electronic device is triggered, the piezoelectric signal converter will then have a breaking rigidity, and the ball striking surface mechanically coupled thereto will have a higher rigidity for subsequent impact.

An electronic circuit that performs this function is very similar to the circuit described above for friction control applications. We modified this electronic circuit to replace inductor L1 with a resistor R12 in Figure 23, while switch M1 in the friction control electronics (this is an N-channel boost modal MOSFET) with a new MOSFET Q12 ( This is replaced by an N-channel depleted modal MOSFET). Due to this depleted modal N-channel MOSFET Q12, the electronic circuit will be in a short-circuit state at the beginning, that is, the switch Q12 is closed. When the voltage at the gate of the MOSFET is lowered (when it is triggered), the depleted modal MOSFET disconnects the electronic circuit, thereby disconnecting the resistor (and thereby cutting off the piezoelectric electrode). The electronic circuit is now in an open state. Controlling the function of the electronic circuit reduces the gate voltage rather than raising the gate voltage like a friction control electronic circuit. These two voltage-driven MOSFET drive electronic circuits are common.

A trigger event is generated when the voltage across the piezoelectric element reaches a threshold voltage transmitted by the Zener diode. The voltage rises because the piezoelectric element is forced to discharge via resistor R12 (and therefore does not have a perfect short circuit). This provides an opportunity to trigger the pressure rise that occurs when the piezoelectric element is stressed. If the piezo element is properly shorted, the voltage will not rise and the trigger will not occur. Since the piezoelectric element is short-circuited at the beginning through the resistor R12 (the switch Q12 is closed at the beginning), as long as the applied force occurs at a speed equal to or greater than the system RC time constant, the voltage rises. If the applied force occurs below this frequency associated with the RC time constant, the voltage will not increase much because the resistance will be shorted. If it is higher than this time constant (ie relatively fast force), the resistor will open and the voltage will rise. The piezoelectric element has substantially no time to discharge through the resistor during this event.

The electronic circuit therefore affects the impact of sufficient speed or intensity (which will increase the voltage across the resistive shunted piezoelectric element), which triggers the electronic circuit and opens the depleted modal MOSFET to effectively break the electronic circuit. The piezoelectric element is placed in an open state. The system therefore stiffens the system when the strength or speed of the impact is sufficient. The system can be adjusted by selecting an appropriate shunt resistor or (primarily) by selecting an appropriate trigger Zener breakdown voltage.

The above system is self-sensing and self-powered. It does not require power from an external source, but instead uses the charge from the signal converter itself connected to the ball striking face. It must be noted that the trigger signal can also come from an alternative sensor; in addition to the more complex feedback logic, it may even be determined by a programmable microprocessor. This microprocessor can supply power from the energy absorbed by the circuit from the impact motion. The microprocessor is externally configured to adapt the system to pre-set conditions (especially for the characteristics and capabilities of individual golfers). This is the concept of a programmable smart club that is designed to take full advantage of the impact of a particular golfer's swing action. Stylization basically adjusts the behavior of the club and can be set for individual golfers and his abilities and abilities. For example, correcting a hook or a ball.

From the above description of various examples of the invention, it will be apparent that many additional variations can be made, and the description herein is merely illustrative of the concepts of the invention. Therefore, the actual scope is not limited to the above description, but only the scope of application and similar designs described later are taken as an example.

10. . . Batting surface

11. . . Head body

12. . . case

13. . . End cap

14. . . Batting surface component

15. . . Piezoelectric end cap assembly

16. . . Backplane assembly

17. . . Detachable component

18. . . Circuit board

19. . . Connection plate

20. . . Fixed joint

twenty one. . . Piezoelectric element

twenty two. . . wire

twenty three. . . End piece

twenty four. . . Lamination

25. . . Strain overflow ring

26. . . Convex

27. . . Threaded surface

28. . . Hex nut

29. . . Thread

30. . . Threaded surface

32. . . hole

33. . . Batting surface

34. . . Outside the ring

35. . . Step difference

36. . . Bevel

37. . . Thread ring

38. . . Ring

39. . . Inside the ring

40. . . Collar

42. . . The inside of the head body

43. . . Club head

44. . . Fixed column

45. . . Fixed column

46. . . Fixed column

47. . . Fixed column

49. . . Connector

52. . . Shell wall

53. . . Bevel

54. . . Bottom plate

56. . . Ring

62. . . Club

105. . . Bending couple

106. . . Force point

205. . . Anchor bolt

206. . . Preload bolt

207. . . Backing structure

208. . . Backing layer

209. . . Reaction block

210. . . Mobile amplifier

211. . . Bisexual bending

212. . . Backplane

Cn. . . Capacitor

Dn. . . Dipole

Ln. . . Inductor

Pn. . . Quartz oscillator

Qn. . . switch

Rn. . . resistance

Specific details, features, and advantages of the present invention will be more fully understood by reference to the detailed description of the following drawings in this section:

1-5 illustrate various conceptually specific examples of the present invention showing various different forms of elastic coupling of a piezoelectric actuator to a ball striking face of a golf club head;

6-8 illustrate various conceptual examples of the present invention, showing various forms of inertial coupling of a piezoelectric actuator to a ball striking face of a golf club head;

Figure 9 illustrates a conceptual embodiment of the present invention in which a piezoelectric signal converter is disposed between the ball striking face and the club body for positioning the ball striking face relative to the body;

10a and 10b are block diagrams of a piezoelectric actuator including control switches, inductors, and circuits;

Figure 11 is a block diagram showing the control circuit of the circuit of Figure 10b in more detail;

Figure 12 is a graphical representation of the output voltage signal of an actuator under impact with a ball, showing the voltage/time transition relationship between untriggered and triggered;

Figure 13 is a graphical representation of the important parameters in the impact of the ball and the club. The figure shows A) impact normal force, B) impact tangent (friction) force, C) signal converter voltage / time transition relationship, D) the signal converter current/time transition relationship, and E) the result of the sphere rotation/time transition relationship;

14-15 are cross-sectional views of the golf club head of FIG. 2 using a conceptual piezoelectric connection, which reduces the friction between the head and the golf ball by converting the impact energy of the ball into the vibration of the face of the club head. Force to reduce the rotational speed of the golf ball;

16a and 16b together form an illustration of a specific example of a golf club head of the conceptual piezoelectric connection of FIG. 2, in which the detachable base plate and the electronic device of the system are presented in detail;

17-19 are detailed explanatory views of the ball striking face assembly, which shows the connection of the piezoelectric signal converter and the ball striking face of the specific example of the conceptual piezoelectric connection of FIG. 2;

Figure 20 is a graphical representation of the friction model of the interaction between the ball striking face and the ball;

Figure 21 is a frequency response function showing the voltage response of the open-circuit piezoelectric signal converter when the ball striking face is subjected to a periodic load;

Figure 22 is a frequency response function showing the surface acceleration of the ball striking face as a function of the voltage excitation amplitude of the piezoelectric signal converter as a function of time;

Figure 23 is a block diagram of a circuit block of a circuit system used to achieve variable stiffness, the stiffness of which depends on the piezoelectric mechanical stimulus of sufficient strength.

10. . . Batting surface

11. . . Head body

twenty one. . . Piezoelectric element

106. . . Force point

207. . . Backing structure

Claims (39)

A golf club head having a ball striking surface for striking a golf ball, the golf club head comprising: a signal converter for converting mechanical energy generated by the impact of the ball striking surface with the golf ball into electrical energy An electronic circuit electrically connected to the signal converter for selective manipulation and application of the electrical energy; and an actuator mechanically coupled to the ball striking surface and capable of affecting the striking due to electrical energy The surface of the ball, and the electrical energy is returned to change the impact of the ball striking surface with the golf ball; wherein the electronic circuit includes at least a control circuit, a switch and an inductor component, the control circuit can drive the switch to The inductor element forms a loop with the signal converter. A golf club head according to claim 1, wherein the signal converter comprises a piezoelectric element. A golf club head according to claim 1, wherein the actuator comprises a piezoelectric element. A golf club head according to claim 1, wherein the signal converter and the actuator comprise a common piezoelectric element. A golf club head according to claim 4, wherein the piezoelectric element is coupled to the ball striking surface. The golf club head according to claim 1, further comprising a support structure disposed in the golf club head, the support structure maintaining the ball striking surface and the actuator Close contact. The golf club head according to claim 4, further comprising a support structure disposed in the golf club head, the support structure between the ball striking surface and the piezoelectric element Keep in close contact. The golf club head of claim 6, wherein the support structure comprises a tapered housing. The golf club head of claim 7, wherein the support structure comprises a tapered housing. A golf club head according to claim 1, wherein the actuator is designed to vibrate the ball striking surface at a selected frequency when the golf ball is struck by the ball striking surface. A golf club head according to claim 1, wherein the actuator is designed to vibrate the ball striking surface at an ultrasonic frequency. The golf club head according to claim 1, wherein the actuator is designed to cause the ball striking surface to vibrate at a frequency and an amplitude sufficient to interrupt contact between the ball striking surface and the golf ball. . The golf club head of claim 1, wherein the electronic circuit includes a reactive impedance to store the electrical energy. The golf club head of claim 1, wherein the electronic circuit includes a reactance to store the electrical energy. The golf club head of claim 1, wherein the inductor element of the electronic circuit stores the electrical energy. The golf club head of claim 1, wherein the electronic circuit includes the inductor and a capacitor to store the electrical energy. A golf club head according to claim 1, wherein the open relationship of the electronic circuit is responsive to a threshold parameter of the ball striking surface against the golf ball to selectively apply the electrical energy. The golf club head according to claim 17, wherein the parameter is returned by the signal converter to an amount of a voltage generated by the impact. A golf club head having a ball striking surface for striking a resting golf ball, the golf club head comprising: a signal converter for converting first mechanical energy striking the golf ball into input electrical energy and used to The output electrical energy is converted into a second mechanical energy; and an electronic circuit is configured to receive the input electrical energy and supply the output electrical energy; the input electrical energy is a pulse signal that should be the first mechanical energy, and the output electrical energy is a shock signal; The electronic circuit includes at least a control circuit, a switch and an inductor component. The control circuit can drive the switch to form a loop between the inductor component and the signal converter. The golf club head according to claim 19, wherein the second mechanical energy is a shock having the frequency of the oscillating signal. A golf club head according to claim 19, wherein the signal converter comprises a piezoelectric element. The golf club head according to claim 21, wherein the piezoelectric element is mechanically coupled to the ball striking face. A golf club head according to claim 21, further comprising a housing in the head, the housing being fixed inside the ball striking face and enclosing the piezoelectric element. A golf club head according to claim 20, wherein the shock is applied to the ball striking face to intermittently interrupt contact between the ball striking face and the golf ball. A method for reducing an effective friction coefficient between a golf club head ball striking surface and a golf ball, the method comprising the steps of: converting energy of a ball striking the ball striking face into ultrasonic vibration of the ball striking face to affect The ball striking face interacts with the ball in the impact. A method for reducing an effective friction coefficient between a golf club head hitting surface and a golf ball according to claim 25, wherein the converting step comprises the steps of: converting the ball impact energy into electrical energy; This electrical energy is converted into the ultrasonic vibration. A method for reducing an effective friction coefficient between a golf club head hitting surface and a golf ball as described in claim 25, wherein the converting step utilizes a piezoelectric element mechanically coupled to the ball striking surface, respectively. get on. A method of changing the interaction between a golf club head ball striking surface and a golf ball struck by the ball striking surface, the method comprising the steps of: joining a piezoelectric element to the ball striking surface to and from the ball striking surface The impact of the golf ball generates a first electrical signal; converting the first electrical signal to a selected second electrical signal; selectively connecting the second electrical signal to the piezoelectric element to produce a mechanical mechanism for the ball striking surface Act to change the behavior of the golf ball. In the method of changing the interaction between the golf club head hitting surface and the golf ball struck by the hitting surface as described in claim 28, the mechanical action is a vibration of a selected frequency, and wherein the behavior It is the resulting rotational speed of the golf ball. A golf club head having a ball striking surface and including a means for reacting the ball striking surface with the golf ball to stiffen the ball striking surface when the impact force exceeds a selected limit, wherein the striking The ball surface is electrically connected to the device in which the ball striking surface is hardened. A golf club head according to claim 30, wherein the device includes a sensor for sensing the impact force and a contact with the ball striking surface and depending on whether the impact force is higher or lower than the impactor The boundary has at least two distinct signal converters with a rigid level. A golf club head according to claim 31, wherein the sensor comprises a piezoelectric element. A golf club head according to claim 31, wherein the signal converter comprises a piezoelectric element. The golf club head according to claim 31, wherein the sensor and the signal converter each comprise a piezoelectric element. The golf club head of claim 31, wherein the sensor and the signal converter comprise a common piezoelectric element. A golf club head includes a variable stiffening element for selectively increasing and reducing the rigidity of the club head surface, wherein the variable stiffening element is disposed within the golf club head. A golf club head according to claim 36, wherein the stiffening element comprises a piezoelectric element having a first level of rigidity in a short circuit condition and a second level of rigidity in an open state. A golf club head according to claim 37, wherein the state of the piezoelectric element is determined by a switch. A golf club head according to claim 38, wherein the switch is controlled by a sensor that reflects the impact level of the golf club head and the golf ball.