JPH08338527A - Decision method of speed pedal motion by closed loop control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To always control speed change properly by setting a zero point representing a position, in which a transmission output speed matches a speed pedal position, on a predetermined control map having a zero point line without any acceleration or deceleration and moving the speed pedal to a new position until the zero point is positioned along the zero point line. SOLUTION: A continuously variable transmission 10 is provided with a hydrostatic transmission 14 connected to an engine 12 via a pump input shaft 17 and a mechanical transmission 18 connected to the engine 12 via a gear device 21. The transmission 10 is also provided with a speed input mechanism 54 having a speed pedal 56 and a command input device 24 including a direction control mechanism 58 having a direction control lever 60, and the output of the command input device 24 is inputted to a microprocessor 22. A position of the speed pedal 56 and an output speed of the transmission are compared with each other so that the zero point is set along the zero point line on a control map, and the transmission acceleration/deceleration control is carried out in compliance with the movement of the speed pedal 56 toward a new value until the zero point is positioned on the zero point line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a method of controlling the motion of a machine with a speed pedal. More particularly, it relates to a method of determining speed pedal movement in a mechanical system having closed loop control.

[0002]

In known open loop hydraulic systems, pedal position is related to pump / motor displacement. Due to leakage and efficiency fluctuations, this type of system does not scale with output speed. As a result, when the throttle position changes, the resulting machine speed will be different for a given speed pedal position. In many cases, it is desirable to have a direct relationship between speed pedal position and machine speed, or to be able to control that relationship in order to have better control of the total power of the machine. This benefits the operator and can be related to his will, i.e. the degree to which the operator presses down the speed pedal and the desired vehicle speed. It would also be of benefit to the operator to have the ability to have more reliable control of machine speed while operating at slower speeds in one direction or the other.

[0003]

In many known systems, the efficiency of the transmission changes under different operating conditions,
The position of the speed pedal in the sense of holding the throttle position constant is not directly related to the output speed produced by the machine. The present invention solves one or more of the above problems.

[0004]

SUMMARY OF THE INVENTION In one aspect of the invention, a method of determining motion of a speed pedal in a continuously variable transmission having closed loop control is provided. The method monitors the output speed of the transmission, monitors the position of the speed pedal relative to the output speed of the transmission, and determines the zero point along a null line on a given control map. Position and the output speed of the transmission, and the steps of accelerating and decelerating the transmission in response to moving the speed pedal to a new position until the zero point is located along the zero line. Prepare The zero point represents the position where the output speed of the transmission balances the speed pedal position. The predetermined control map is divided into a first region related to the acceleration of the transmission and a second region related to the deceleration of the transmission, and a zero line where neither the acceleration nor the deceleration of the transmission is in between. Is formed. The present invention provides a method of directly relating the position of the speed pedal to the output speed of the transmission. This allows the operator to make an input to the speed pedal and to expect a constant speed output from the transmission whenever the same input is made to the speed pedal. Further, if desired, a system can be provided such that control of speed in the first part of the speed pedal run is more reliable than control in other parts of the run.

[0005]

DETAILED DESCRIPTION Referring to FIG. 1, a continuously variable transmission 10 is shown for use with a machine having an engine 12 (not shown). The continuously variable transmission 10 includes a hydrostatic transmission 14 operatively connected to the engine 12 via a pump input drive shaft 17, and a hydrostatic control device 16 combined with the hydrostatic transmission 14. A mechanical transmission 18 operatively connected to the engine 12 via a gear device 21.
A clutch controller 20 combined with the mechanical transmission 18, a microprocessor 22 operatively connected to the hydrostatic controller 16 of the hydraulic transmission 14 and the clutch controller 20 of the mechanical transmission 18. , A sensing device 23 and a command (operator) input device 24. The work system 26 uses the final drive shaft 28 to drive the continuously variable transmission 10
Is combined with Mechanical transmission 18 includes a compound planetary device 30 operatively coupled to both engine 12 via gearing 21 and hydraulic transmission 14 via motor output shaft 34. The output of the compound planetary device 30 is coupled to the final drive shaft 28. Mechanical transmission 18 also includes directional high speed clutches 36, 38 and low speed clutch 40. Clutch controller 20 is coupled to a source of pressurized pilot fluid, such as pilot pump 42, and microprocessor 22 and operates in response to receiving an electrical signal from microprocessor 22 to provide individual speed clutches 36, 38 ,. It controls the engagement and disengagement of 40.

The hydraulic transmission 14 is a pump displacement amount controller 4.
6 and a variable displacement motor 48 having a motor displacement controller 52 in fluid communication with the variable displacement pump 44 by conduits 49, 50. The hydrostatic control device 16 is connected to the pilot pump 42 and the microprocessor 22, operates by receiving an electric signal from the microprocessor 22, and controls the motion of each pump and the motor displacement amount controllers 46 and 52. The command input device 24 includes a speed input mechanism 54 having a speed pedal 56 movable from a maximum speed position to a zero speed position,
A direction control mechanism 58 having a direction control lever 60 selectively movable from a neutral position to a forward position or a retracted position. Sensing device 23 includes a first speed sensor 62 that operates to sense the speed of pump input shaft 17 and send a representative electrical signal to microprocessor 22. The second speed sensor 64 operates to sense the speed of the motor output shaft 34 and send an electrical signal representative thereof to the microprocessor 22. The third speed sensor 66 operates to sense the speed of the final drive shaft 28 and send an electrical signal representative thereof to the microprocessor 22.

Referring to FIGS. 2-5, a control map 68 is shown. The vertical axis of the control map is the zero travel position (0
%) And its maximum travel position (100%). The horizontal axis of the control map relates to the speed of the machine or the output of the transmission between zero speed (0%) and maximum speed (100%). The control map 68 generally illustrates the relationship between the operator's "will" and the speed command input made through the speed pedal 56, such that when the speed pedal 56 is moved from one position to another, the machine Accelerate or decelerate. The control map 68 is a zero line 74 formed between the first map 70 and the second map 72.
Can be divided into The zero line 74 represents a zone where the machine is neither accelerated nor decelerated. In other words, this zone is where the position of the speed pedal 56 and the output speed of the final drive shaft 28 relative to the work system 26 balance. From that position, if you move the speed pedal 56 in either direction,
This results in the operation of the continuously variable transmission 10 to increase or decrease the speed of the final drive shaft 28 that is applied to the work system 26. The first area 70 of the control map 68 is associated with the zone of mechanical acceleration and the second area 72 is associated with the zone of mechanical deceleration. Under this control map 68, the speed pedal 56 operates as a pure accelerator when the machine is at zero speed,
When the machine is at maximum speed, the speed pedal 56 operates as a pure brake.

Referring to FIGS. 3-5, various examples are shown. FIG. 3 represents the movement of the speed pedal 56 from its zero travel position to its 50% travel and the changes that occur within the speed of the machine, which are related to the maximum speed of the machine. Continuously variable transmission 1
The point where the speed of 0 balances the position of the speed pedal 56 (the operator's will) is marked as the null point. As mentioned above, this is the final drive shaft 28 driving the machine.
There is no acceleration or deceleration of. FIG. 4 shows the movement of the speed pedal 56 from the 50% travel position to the 25% travel position and the change in the position of the zero point after that. The change in the position of the zero point indicates the speed generated in the machine. Represent In addition, the degree of acceleration, that is, the "urgency" of acceleration, is determined by the new position and zero line 7.
4 and the vertical distance on the control map. The longer the distance, the faster the machine will accelerate. Acceleration is limited by the available power of the system. FIG. 5 shows the movement of the speed pedal 56 from the 25% travel position to the 75% travel position and the change in the position of the zero point after that. The change in the position of the zero point indicates the speed generated in the machine. Represent The degree of deceleration, or "urgency" of deceleration, is also determined by the vertical distance on the control map between the new position and null line 74, as described above. The longer the distance, the faster the machine will slow down.

Another control map 68 is shown in FIGS. The control maps of FIGS. 6 and 7 have a non-linear null line 74.
Other than that, the control map is almost the same as the control map in FIG. 2-5. By providing a non-linear zero line 74, the speed is provided to provide fine and coarse adjustments of the machine speed during movement of the speed pedal 56 in the first position of the run, as compared to the holding portion of the run. Movement of the pedal 56 can be made. In the control maps 68 of FIGS. 6 and 7, the movement of the speed pedal 56 results in a fine adjustment of the machine speed during one part of the run when compared to the motion in another part of the run. As shown, movement of the speed pedal 56 for the 75% travel position results in a lesser machine speed when compared to the same position shown in FIG. Further, as shown in FIG. 7, movement of the speed pedal 56 for the 25% travel position results in different vehicle speeds when compared to the same position of the speed pedal 56 shown in FIG. Various configurations may be utilized without departing from the essence of the invention. For example, the zero line 74 can be reshaped to suit the needs of the system, if desired. Furthermore, another type of continuously variable transmission 1
0 can be used. In addition, the speed pedal movement is
As described above, the machine speed control from the zero speed to the maximum speed may be performed instead of the speed control from the maximum speed to the minimum speed.

In the operation of this embodiment, a directional input is made to the directional lever 60 to select the traveling direction. In this device, the continuously variable transmission 10 accelerates to its maximum speed while the speed pedal 56 is at the zero travel position. To accomplish this acceleration, the microprocessor 22
Receives an electrical signal representing the position of the speed pedal 56 and the directional lever 60, and processes a command representing the operator's will,
Appropriate signals are sent to the hydrostatic control device 16 and the clutch control device 20. First, the hydraulic transmission 14 regulates the individual displacements of the variable displacement pump 44 and the variable displacement motor 48, and controls the individual speed clutches 36, 38, 40 to continue increasing the machine speed. Increases the speed of the machine. A further speed increase is achieved by controlling the speed of the ring gear of the compound planetary device by actuating the high speed clutch. When the desired maximum speed condition is reached, the microprocessor 22 maintains a constant machine speed that does not accelerate or decelerate the machine. Due to the dynamic content of the system, when the machine speed "overshoots" (overshoots) the specified value at the zero line, the microprocessor 2
2 automatically performs the necessary corrective action and the zero line 7
Adjust speed towards 4.

When it is desired to slow the output speed of the continuously variable transmission 10, that is, the speed of the machine, the operator pushes the speed petal downward a desired amount. When the operator pushes the speed petal down to 50% of its mileage, as mentioned above, the machine is traveling at its maximum speed,
Machine speed is reduced. With reference to the control map of FIG. 3, when the speed pedal 56 is pushed down 50%, the machine slows or slows until the speed of the machine balances the position of the speed pedal 56. This continuously monitors the output speed of the final drive shaft 28 via the third sensor 66,
This is accomplished by the microprocessor 22 comparing the sensed speed with the desired speed as sensed by the signal from the position of the speed pedal 56. As the speed decreases, the relationship between the position of the speed pedal 56 and the machine speed becomes
It is compared on the control map 68. The zero point is the zero line 74
Upon reaching the top, the microprocessor 22, as required, sends appropriate signals to the individual hydrostatic and clutch controls 16 and 20 to provide a constant machine speed without acceleration or deceleration. Hold. As long as the operator does not change the position of the speed pedal 56, the machine speed will be
Holds constant at approximately 50% of maximum speed.

Referring to the operation of the control map of FIG. 4, the speed petal 56 is moved from the 50% travel position to the 25% travel position. Following the movement of the speed petal 56, the microprocessor 22 senses that the continuously variable transmission 10 needs to be accelerated. The appropriate signal is sent to the appropriate hydrostatic controller 16 and clutch controller 20 to increase the speed of the machine. The machine speed is increased until the machine speed balances the position of the speed pedal 56 along the zero line 74 of the control map 68. At this null, the microprocessor 22 suspends acceleration and maintains a constant speed of approximately 75% of maximum speed. Referring to the operation of the control map of FIG. 5, the speed pedal 56 is moved from the 25% traveling position to the 75% traveling position. Following the motion of the speed petal 56,
The microprocessor 22 senses that the continuously variable transmission 10 needs to be decelerated. The appropriate signal is sent to the appropriate hydrostatic controller 16 and clutch controller 20 to reduce the speed of the machine. The machine speed is reduced until the machine speed balances the position of the speed pedal 56 along the zero line 74 of the control map 68. At this zero point, the microprocessor 22 interrupts the deceleration and reaches a maximum speed of approximately 2
Hold a constant speed of 5%.

Referring to the operation of the control map of FIG. 6 where the zero line 74 is non-linear, when the speed pedal 56 is pushed downwards to its initial position of zero travel, ie, 75% of full speed travel position, The speed of the machine is reduced until the speed of the machine along zero line 74 balances the position of speed pedal 56. When the zero point is reached, the microprocessor 22
Holds the machine at a constant speed of approximately 10% of maximum speed. In this control map 68, the zero line 74 is non-linear and the convex shape extends away from the deceleration portion 72 to the acceleration portion 70, so that during a portion of the travel of the speed pedal 56, the machine speed is more finely divided. Can be controlled. With this device, for each increase in travel from the 100% travel position to nearly 20% travel position, the change in vehicle speed is less than in the travel hold. The shape of the null line 74 can be varied to suit various system requirements. Referring to the operation of another control map of FIG. 7, the speed pedal 56 is moved from the 75% travel position to the 25% travel position. Following the movement of the speed petal 56, the microprocessor 22 senses that the continuously variable transmission 10 needs to be accelerated. The appropriate signal is sent to the appropriate hydrostatic controller 16 and clutch controller 20 to increase the speed of the machine. The machine speed is increased until the machine speed balances the position of the speed pedal 56 along the zero line 74 of the control map 68. At this null, the microprocessor 22 suspends acceleration and maintains a constant speed of approximately 40% of maximum speed. In this device, the machine speed does not drastically increase with respect to the moving amount of the speed petal 56. From a review of FIGS. 6 and 7, the machine changes speed more rapidly for each increase in travel of the speed petal for the first part of the speed petal motion, 0% to approximately 20%. Therefore, at slower speeds, the operator has a more precise control of the speed of the machine. If it is necessary to have a more rapid change in machine speed in the final part of the speed petal movement, the control map null line 74 may be shaped to meet that need.

Thus, the method of determining the motion of the speed petal 56 in the continuously variable transmission 10 having closed loop control includes a step 66 of monitoring the output speed of the transmission, a speed petal related to the output speed of the transmission. Position monitoring 54, comparing the position of the speed petal to the output speed of the transmission to establish a zero along a zero line 74 on a predetermined control map 68, and It consists of accelerating and decelerating the transmission in response to moving the speed petal to a new position until it is positioned along the null line 74. The zero point represents the position where the output speed 28 of the transmission balances the speed petal position. The predetermined control map 74 is divided into a first region 70 related to the acceleration of the transmission and a second region 72 related to the deceleration of the transmission, during which there is no acceleration or deceleration of the continuously variable transmission 10. A null line 74 is formed. Further, in this way, the null line 74 of the control map 68 may be a straight line or any non-linear shape required to meet the requirements of the system. Also, in the step of monitoring the position of the speed petal, the movement of the speed petal in a part of the moving stroke is less than the rate of increase or decrease when moving in the remaining part of the moving stroke. There is an increase or decrease in speed of 10.

From the above, the method of the present invention provides a process for determining the motion of the speed petal 56 in the continuously variable transmission 10 having closed loop control, and accurately controls the speed of the machine based on the position of the speed petal 56. What to do will be readily apparent. Other objects and advantages of the invention will be apparent from the drawings and description, and from the appended claims.

[Brief description of drawings]

FIG. 1 is a partial block diagram of a mechanical system utilizing the subject method.

FIG. 2 is a control map showing the relationship between speed pedal position and machine output speed.

FIG. 3 is a diagram including a control map of FIG. 2 and showing a relationship with a speed pedal in an operating position.

FIG. 4 is a diagram including the control map of FIG. 2 and showing a relationship with a speed pedal in another operating position.

FIG. 5 is a diagram including the control map of FIG. 2 and showing a relationship with a speed pedal in still another operating position.

FIG. 6 is another control map showing the relationship between the speed pedal position and the output speed of the machine with the speed pedal in one operating position.

FIG. 7 is a diagram that includes the control map of FIG. 6 and shows the relationship between the speed pedal position and the output speed of the machine, together with the speed pedal at another operating position.

[Explanation of symbols]

 10 continuously variable transmission 12 engine 14 hydraulic transmission 16 hydrostatic control device 18 mechanical transmission 20 clutch control device 22 microprocessor 23 sensing device 24 command input device 26 working system 28 final drive shaft 30 synthetic planetary device 34 motor output shaft 36, 38, 40 Speed clutch 42 Pilot pump 44 Variable displacement pump 46 Pump displacement amount controller 48 Variable displacement amount motor 49, 50 Conduit 52 Motor displacement amount controller 54 Speed input mechanism 56 Speed pedal 58 Direction control mechanism 60 Direction control Lever 62, 64, 66 Speed sensor 68 Control map 70 First area 72 Second area 74 Zero line

Claims (7)

[Claims] 1. An output speed of a continuously variable transmission is monitored, a position of a speed petal related to the output speed of the transmission is monitored, and the speed petal position is compared with the output speed of the transmission. , A first area related to acceleration of the transmission and a second area related to deceleration of the transmission, and a zero line is formed between the first area and the second area related to deceleration of the transmission. A zero point is defined on the predetermined control map, which represents a position where the transmission output speed balances the speed pedal position, and the speed petal is moved to a new position until the zero point is located along the zero line. Determining the movement of a speed pedal in a continuously variable transmission having closed loop control, the method comprising accelerating and decelerating the transmission according to. 2. The method of claim 1, wherein in the step of comparing the speed petal and the output speed of the transmission, the null line is substantially linear. 3. The method of claim 2, wherein in the step of monitoring the position of the speed petal, the speed petal is movable from a maximum speed position to a zero speed position. 4. The method of claim 1, wherein in comparing the speed petal and the output speed of the transmission, the zero line is substantially non-linear. 5. The method according to claim 4, wherein in the step of comparing the speed petal and the output speed of the transmission, the first region is smaller than the second region. 6. The step of monitoring the position of the speed petal, wherein the movement of the speed petal in the first part of the range of motion of the speed petal is higher than the rate of increase or decrease when operating in the remaining range of motion. The method according to claim 5, wherein the method increases or decreases at a small rate. 7. The method of claim 6, wherein in the step of monitoring the position of the speed petal, the speed pedal is changeable from a maximum speed position to a zero speed position.