CZ307670B6 - Positioning device for rehabilitation robot - Google Patents

Abstract

A positioning device (13) for a rehabilitation robot with a parallel kinematic chain structure comprising a base plate (1) pivotally connected to the first effector plate (4) by a triple arm (2) driven by the motors (3) where the base plate (1) is provided with three fluid motors (3) which are provided with control shafts (5) which are arranged at an angle of 120 ° to each other and are arranged perpendicular to the longitudinal axis (18) of the beam (8) through which the control shaft extends at one end (5) and at the other end a connecting shaft (9), wherein each arm (2) is formed by a beam (8) and a pair of rods (11) provided with joints (10) at their ends and arranged in parallel and spaced from each other and connected by means of connecting shafts (9) which are mounted in the joints (10), the first effector plate (4) being connected to the connecting shafts (9) by means of connecting elements (12), where between p a sensor (17) for sensing forces and moments of force is provided by the second effector plate (15) by the first effector plate (4), the second effector plate (15) being provided with a gripping element (7).

Description

Positioning device for rehabilitation robot

Technical field

The invention relates to a positioning device for a rehabilitation robot provided with a parallel kinematic chain structure comprising a base plate movably coupled to an effector plate by means of a triple arm driven by motors, wherein the positioning device for the rehabilitation robot is equipped with a force and torque sensor for feedback-controlled and active re-education of movement of limbs affected by loss-of-movement disorders.

BACKGROUND OF THE INVENTION

Rehabilitation robots are designed for reeducation of movement of patient's limbs, which are affected by lossy diseases of their mobility. And they are based on the use of biological feedback, biofeedback, usually visual. Where a patient whose affected limb is attached to the robot effector should follow the desired trajectory of movement. Rehabilitation robot allows to move the effector only in the desired trajectory of movement, using sensors to monitor the patient's effort and the resulting muscle strength. Sensors built into the robot's motion mechanism evaluate the success of this patient's effort, and in case of failure, the robot itself gently and gently adopts the desired movement, but only for a partial, usually short section of the desired trajectory, again giving the patient a chance. This process is repeated, so that after many repetitions of the desired movement, the patient gains a chance to establish new neural connections. The formation of new neural connections occurs by utilizing the neuroplasticity of the central nervous system. In this way, the patient learns to regain the lost momentum of his affected limb. In this rehabilitation procedure, it is very important to ensure the movement of the patient's limb by an interactive and cooperating rehabilitation robot. In the so-called end-effector of rehabilitation robots, the robot is guided by the robot with the loss of momentum, so that it is attached by its end-effector to its distal part. In this case, various mechanisms and kinematic chains are used to optimally guide the patient's limb.

EP 0016094 discloses a programmable exercise machine. The exercise machine consists of two arms. The arms are arranged in series and connected to each other by a swivel joint. The rotary joint is provided with a separate drive which rotates the rotary joint. The user moves the effector located on the furthest arm. The movement of the effector is influenced by both the user's limb and the self-drive and is controlled by the feedback system. The feedback system ensures that the effector moves along a predetermined trajectory by the force exerted by the user while providing resistive forces that are arbitrarily different in position, speed, time or force exerted by the user.

The limb rehabilitation device described in CN 105581891 comprises a pivot mechanism, a telescopic mechanism and a movable arm. The pivot mechanism comprises a rotary drive device and a pivot arm coupled to the rotary drive device. The pivot arm is rotated around a fixed shaft by a rotary drive device. One end of the pivot arm that is located near the fixed shaft is called the fixed end. The other end is called the pivot end. Two pivot joints are arranged on the pivot arm. The pivot joint located near the fixed end is referred to as the first pivot joint, and the pivot joint located at the opposite end of the pivot arm is referred to as the second pivot joint. One end of the pivot arm is rigidly connected to the effector, while the other end is connected to the pivot arm in the other pivot connection. The telescopic mechanism includes a telescopic drive device and a telescopic arm coupled to the telescopic drive device.

- 1 GB 307670 B6

US 9403056 discloses a rehabilitation system that allows patients to improve the coordination of forearm and hand movements. The rehabilitation system includes a multi-degrees of freedom effector that is provided with means for providing precisely modulated resistive forces and precisely modulated driving forces. The rehabilitation system further includes a virtual reality simulation display device through which the effector trajectory is displayed. The sensing device of the rehabilitation system enables sensing of force, load, torque, angular displacement, angular velocity, displacement and / or effector position. The rehabilitation system control unit includes a memory for storing the effector movement data and a processor for calculating the resistance forces and the effector movement forces. The means for providing precisely modulated resistive forces comprises a hydraulic circuit with a pump which is connected to the control unit.

It is clear from the prior art that the locomotion device of rehabilitation robots comprises an arm consisting of two parts which are connected to each other by means of a rotary joint. The first part has a fixed end, while the second part has a movable end. The movable end is connected to the effector. The movement of the arm is ensured by a drive arranged at the pivot point or at the fixed end. The arm is equipped with sensors to monitor the movement of the effector. The rehabilitation robot further comprises a processing unit that receives data from the sensors. The processing unit includes a memory in which the desired effector movement data is stored. The processing unit compares the data received from these sensors with the data stored in the memory. The result of the data comparison is the movement of the effector. The movement of the effector is controlled by a drive that is connected to the processor unit.

Disadvantages of the devices known from the prior art can be seen in the fact that the positioning devices of the rehabilitation robots and their arms are stressed on the bending, in particular the stresses on their proximal parts. Moreover, their moving parts of the device have a considerable weight.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positioning device for a rehabilitation robot that provides both sufficient rigidity without excessive bending loading and minimizes stress on the proximal parts of the positioning device. It also ensures the low weight of the moving parts of the positioning device, its simple manufacture and assembly, as well as the smooth and flexible movement of the arms of the positioning device, while at the same time achieving a wide range of torque span.

The above object is achieved by a positioning device for a rehabilitation robot with a parallel kinematic chain structure, comprising a base plate pivotally connected to the first effector plate by means of a triple-arm driven engine having the base plate provided with three fluid motors, which are provided with control shafts arranged at 120 ° to each other and perpendicular to the longitudinal axis of the beam through which the control shaft passes at one end and the coupling shaft at the other end, each arm being a beam and a pair of rods which are articulated at their ends and are arranged parallel and spaced from one another and connected by means of connecting shafts which are mounted in joints, the first effector plate being connected to the connecting shafts by means of connecting elements, wherein between the first a sensor for sensing forces and torques is provided by the second effector plate, the second effector plate being provided with a gripper carrier.

Advantageously, the positioning device utilizes a parallel structure of the kinematic chain, the arms of which are placed in a circle at an angle of 120 ° on both the effector plate and the base plate. Also provided are 120 ° angles on the base plate of motors whose control shafts have an axis of rotation arranged in the plane of the base and perpendicular to the axis of the arm support. The planar parallel arrangement of the base plate and the effector plates allows to move the effector plate in a very large working space. An advantage of such an arrangement of the positioning device is

-2GB 307670 B6 optimum drive utilization, optimum power transmission, low weight of moving parts, flexibility and smoothness of movement.

A parallel kinematic chain structure is used to ensure optimal drive utilization, optimum power transmission, sufficient rigidity, to avoid excessive bending loads on the positioning device elements, and to ensure low weight of the movable parts of the positioning device.

To ensure proper rehabilitation and / or re-education of the movement of the limb affected by the loss of its momentum, using the feedback biological feedback (both visual and through proprioreceptors from the affected limb), ie on a neurolysiological basis, a force and torque force sensor is arranged between the first and second effector plates. The force and torque force sensor is connected to the control unit, which allows the rehabilitation robot to track the patient's efforts to move the grip carrier and the muscle force thereafter. The force and torque sensor sends the measured data to the control unit, which stores it in memory and then evaluates the success of this patient effort against the desired effector trajectory through a software application. The control unit is also connected to the fluid motor and adjusts the effector trajectory in case of failure by the patient. And only for a partial, quasi-infinitimally short section of the desired trajectory, and again provides a chance for the patient's free motor effort. This is repeated, so that after many repetitions of the desired movement the patient gains a chance to establish new neural connections. The formation of new neural connections occurs by utilizing the neuroplasticity of the central nervous system.

An advantage is also that the control shafts of the fluid motors are provided with a control shaft rotation sensor. The control shaft rotation sensors are connected to the control unit, which allows the position of the gripper carrier to be continuously monitored and controlled, thus increasing the accuracy of the procedure or recalibrating the entire device.

To ensure the smooth movement of the positioning device, the drives are designed as fluid motors, ie pneumatic or hydraulic. Fluid motors are rotary oscillating fluid motors that rotate the control shaft over an angle of at least 90 °. The fluid engines in the parallel structure of the kinematic chain of the positioning device provide a smooth movement of the arms as well as the required wide torque interval, and it is not difficult to reach intervals ranging from tenths of Nm to hundreds of Nm. Fluid motors have electrically controlled solenoid valves arranged upstream and downstream of the piston. Each electrically controlled valve rotates the engine control shaft in one direction.

To provide automatic control of the solenoid valves arranged on both sides of the fluid engine piston, all valves are controlled by pulse width modulation, the modulation level, i.e. the width of the periodically repeating pulses, controlled by proportional (P) -integral (I) - derivative (D), respectively proportionally (P) - summation (S) -differential (D) controller (PID, PSD) with constants of its P, I, D members suitably selected to achieve optimal controller function. At the same time, only a small pressure difference is maintained on both sides of the pistons of the fluid motors, so that the motors are controlled as servo-pneumatic or servo-hydraulic drives, respectively.

The advantage of using fluid motors is that they can do without complex self-locking transmissions, providing a flexible torque control solution, as well as greater safety and flexibility of the rehabilitation robot's locomotor against the treated limb, as well as providing a simpler design.

The advantages of using fluid motors in rehabilitation robots can be summarized as follows:

• easy distribution of working medium over longer distances, • simple change of direction of movement,

• wide intervals of the achieved torque forces, • easy change of the speed of movement, • possibility of automatic regulation of the operation of the fluid mechanisms.

Clarification of drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a positioning device with a parallel structure of a kinematic chain for a rehabilitation robot, FIG. 2 shows a different view of the positioning device including a detail of the control shaft bearing in the drive unit, and FIG. The fluid circuit of the drive units is shown as well as the schematic connection of the electrical components of the positioning device for the rehabilitation robot.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be elucidated in the following description by way of example with reference to the accompanying drawings. The solution according to the invention is an arrangement of a rehabilitation robot using a positioning device with a parallel structure of the kinematic chain, where the movement of the effector is ensured by three arms 2, each consisting of two parts.

Fig. 1 shows an embodiment of a positioning device with a parallel structure of a kinematic chain for a rehabilitation robot. The positioning device 13 in this embodiment comprises a base plate 1 which is rotatably connected to the effector plate 4 by means of a triple arm 2. The plate 1 is provided with three fluid motors 3 arranged in a circle at an angle of 120 ° to each other. The arms 2 consist of two parts which form a beam 8 and a set of two parallel bars 11 which are connected to each other. The connection of the two parts of each arm 2 is articulated, and the articulation of the arms 2 to the first effector plate 4 is also provided as articulation. The two parallel rods 11 are spaced from one another and are connected by means of connecting shafts 9 which are rotatably mounted in the joints 10. The joints 10 are designed as omnidirectional joints. The parallel rods 11 in this embodiment are further connected at both ends by a spring 6.

As shown in FIG. 2, the first effector plate 4 is connected to the connecting shafts 9 by means of connecting elements 12 which are also arranged at an angle of 120 ° to each other. The connection of the arms 2 to the fluid motor 3 is realized via a control shaft 5 and a beam 8, the opening of which is provided with a hub or bearing. Referring further to Figures 1 and 2, the arms 2 are arranged at an angle of 120 ° on both the first effector plate 4 and the base plate 1, and the base plate 1 and the first effector plate 4 are arranged parallel. The first effector plate 4 is further provided with a force and torque force sensor 17, which is connected to the second effector plate 15, which is provided with a gripper carrier 7. The force and torque sensor 17 is designed as a three-dimensional strain gauge sensor.

As shown in FIG. 2, each fluid motor 3 is connected to a control shaft 5 rotatably supported therein, each control shaft 5 being mounted such that its axis of rotation is perpendicular to the longitudinal axis 18 of the beam 8. Ends of the beam 8 are provided with holes, one of which passes through the control shaft 5 and the other through the connecting shaft 9, which connects the ends of two parallel rods 11 of the arm 2.

In an exemplary embodiment of a positioning device for a rehabilitation robot, the motor 3 is designed as a fluid motor 3 that rotates the control shaft 5 at least 90 °. The fluid engine 3 is a pneumatic or hydraulic engine 3, which is driven by a working medium, i.e. by compressed air or low pressure hydraulic fluid. The fluid motor 3 comprises a body in which a piston is arranged. The body is provided with fluid inlets on opposite sides. On the first entry

The valve 22a is arranged upstream of the piston of the fluid engine 3 and at the second inlet there is a valve 22b downstream of the piston of the fluid engine 3.

Fig. 3 shows the fluid circuit of the drive units as well as the schematic connection of the electrical components of the positioning device 13 for the rehabilitation robot. The pressurized working medium is supplied by the fluid inlet 14 to the valve block 21 by means of a pump or compressor. The working medium is compressed air or low pressure hydraulic fluid. The valve block 21 is embodied as a housing, a solid material block in which the inlets for the first valves 22a are provided, which valves are located upstream of the fluid engine piston) and the second valves 22b are located downstream of the fluid engine piston 3. In block 21, three pairs of first valve 22a and second valve 22b are connected, which are further connected by piping to individual fluid motors 3. The piping of the first valves 22a is connected before the piston of the fluid motor 3 and the piping of the second valves 22b is connected after the piston of the fluid motor 3. In the periodic pulses, the width (duration) of which is determined by pulse width modulation, fluid is supplied through the first valve 22a or the second valve 22b, based on the desired direction of rotation of the control shaft 5.

Also shown in FIG. 3 is the wiring of the electrical components of the positioning device 13 where the control unit 19 including the PID (PSD) controller is connected to the pulse width modulation block 20. The pulse width modulation block 20 is connected to the first valves 22a and the second valves 22b, which are designed as electrically operated valves. The control unit 19 is further coupled with sensors, which are the steering shaft rotation sensor 16 and the force and torque sensor 17. The steering shaft rotation sensor 16 is arranged on the steering shaft 5 and senses the steering shaft rotation angle 5. The data from the steering shaft rotation sensor 16 and the force and torque sensor 17 are sent to the control unit 19. Via the first valves 22a and the second valves 22b the air or hydraulic fluid pressure is supplied upstream or downstream of the piston of the fluid motor 3, wherein the pulse width (duration) of the rapid periodic switching of the first valves 22a and the second valves 22b is controlled by the pulse width modulation block 20 thereby controlling the desired movement of the control shafts 3. By means of a control from the pulse width modulation block 20 connected to the block 19 including the PID and PID respectively. The PSD regulator maintains a small pressure differential on both sides of the piston of the fluid motor 3, and the fluid motor 3 is controlled as a servo-pneumatic or servo-hydraulic drive.

The desired movement of the control shaft 5 is calculated by means of a software application which is stored in the memory of the control unit 19. Further, the trajectory of the movement of the gripper carrier 7 is stored in the memory of the control unit 19. The control unit 19 has a PID function, respectively. PSD regulator (proportional and integral, respectively summing and derivative, respectively differential regulator), or another type of control system, which is able to receive data on the desired trajectory of the grip carrier 7, recalculate this data to the control shaft 5 and send a signal into the fluid motor 3, which rotates the control shaft 5. The control unit 19 uses the current position of the control shaft 5 of the motor 3 from the control sensors 16 of the control shaft 5. The control unit 19 further uses data on the magnitude of forces acting on the gripper carrier 7 through the force and torque sensor 17. The control unit 19 processes the data from the steering shaft rotation sensors 16 and the force and torque sensor 17 and compares their vectors with the instantaneous desired position on the trajectory of the gripper gripper 7. And, by means of the first valves 22a and the second valves 22b, it controls the fluid motors 3 individually to achieve the desired movement of the gripper carrier 7. The control shaft rotation sensors 16 allow to monitor and control the actual position of the effector with the gripper grip 7 arranged on the second effector plate 15, and the force and torque sensor 17 allows to monitor the muscle force induced by the patient. The control unit 19, by means of a software application, evaluates the success of this patient effort with respect to the desired trajectory of the grip carrier 7. The control unit 19 is also connected to the fluid motor 3 and, in the event of failure by the fluid motor 3, adjusts the trajectory of the gripper carrier 7 by moving it. And only for a partial, usually short section of the desired trajectory, then again provides a chance to the patient. This is repeated, so that after many repetitions of the desired movement, the patient gets a chance to create new ones

Nerve connections. The formation of new neural connections occurs by utilizing the neuroplasticity of the central nervous system.

Industrial applicability

The positioning device for the rehabilitation robot utilizing hydraulic or pneumatic drives is used in medicine as an assistance robot for the robotic rehabilitation of the limbs of patients suffering from loss-of-movement disorders.

PATENT CLAIMS

Claims (22)

A positioning device (13) for a rehabilitation robot with a parallel kinematic chain structure, comprising a base plate (1) pivotally connected to the first effector plate (4) by means of a triple arm (2) driven by motors (3), The base plate (1) is provided with three fluid motors (3) which are provided with control shafts (5) arranged at 120 ° with respect to each other and which are arranged perpendicular to the longitudinal axis (18) of the beam (8) through which at one end of the control shaft (5) and at the other end of the propeller shaft (9), each arm (2) being formed by a beam (8) and a pair of rods (11) which are hinged at their ends and arranged parallel and spaced from one another and connected by means of connecting shafts (9), which are mounted in joints (10), the first effector plate (4) being connected to the connecting shafts (9) by means of joints A sensor (17) for sensing forces and torques is provided between the first effector plate (4) and the second effector plate (15), the second effector plate (15) being provided with a grip carrier (7). Positioning device (13) according to claim 1, characterized in that the control shaft (5) is provided with a control sensor (16) of the control shaft (5). Positioning device (13) according to claim 1, characterized in that the pair of rods (11) is connected to each other by a spring (6) at both ends. 3 drawings List of reference marks: 1 - base plate 2 - arm 3 - motor 4 - first effector board 5 - control shaft 6 - spring 7 shows the grip element carrier 8 - beam 9- connecting shaft 10- kloub 11 - rod 12 - connecting element 13 - positioning device 14 - fluid inlet 15- second effector plate 16 - Steering shaft rotation sensor 17 - force and torque sensor 18 - axis of the shaft arm 19 - control unit 20 - pulse width modulation block 21-valve block -6GB 307670 B6 22a - valve in front of the engine piston 22b - valve after piston of first engine