JPH0688218B2 - Walking leg control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a walking control device for a walking machine including an articulated leg mechanism, and particularly to reduce the torque required to drive the joints of the leg mechanism. The present invention relates to a suitable walking control device.

[Conventional technology]

Conventionally, as a method of improving the walking movement efficiency of a walking machine equipped with an articulated leg mechanism, a method of changing a stride during walking by a leg mechanism has been proposed by the Society of Instrument and Control Engineers (Vol.1, No.7).
1979-2, p76-81).

[Problems to be Solved by the Invention]

The above-mentioned conventional technology refers to the existence of a stride that minimizes the energy consumption of the entire walking machine moving at a predetermined moving speed, and regarding the suppression of the actuator output torque for driving the leg mechanism in the walking machine, This is not taken into consideration, and there is a problem that it is not possible to realize walking that makes maximum use of the drive capacity of the actuator.

An object of the present invention is to provide a walking leg control device capable of minimizing the output torque of a leg mechanism driving actuator in a walking machine.

[Means for Solving the Problems]

In order to achieve the above object, in a walking control device of the present invention, a speed command unit that outputs a target moving speed of a walking machine, a parameter generating unit that determines a stride of a leg motion based on the target moving speed, and a decision A pattern generation unit that generates a position control target value of the joint of the leg mechanism based on the stride obtained, and a joint control unit that controls the position of the joint of the leg mechanism based on the position control target value.

Further, for the same purpose, a first parameter generating unit that determines a stride that minimizes the root mean square value of the leg joint drive torque in accordance with the target moving speed from the speed command unit, and the leg corresponding to the target moving speed. A second parameter generation unit that determines a stride for minimizing the maximum value of the joint drive torque; and a torque calculation unit that calculates the maximum value of the leg joint drive torque from the motion of the leg mechanism,
A parameter selection unit that selects the stride output from the first parameter generation unit or the second parameter generation unit based on the information from the torque calculation unit, and that calculates and outputs the walking cycle based on the target moving speed and the stride, and the parameter selection It is also possible to include a pattern generation unit that generates a position control target value of the leg mechanism joint based on the stride and the walking cycle that are selectively output from the section, and a joint control unit that controls the position of the leg mechanism joint based on the position control target value. it can.

[Action]

In the former walking leg control device described above, the speed command unit outputs the target moving speed to the parameter generation unit. The parameter generation unit outputs to the pattern generation unit a parameter that determines the stride length of the leg motion according to the target moving speed. The pattern generation unit generates a position control target value of the joint of the leg mechanism by the parameter that determines the stride, and outputs this to the leg drive unit. Thus, the joint control unit can drive the leg mechanism, change the stride according to the change in the target moving speed, and suppress the joint drive torque of the leg mechanism during walking to the necessary minimum.

In the latter walking leg control device described above, the parameter selection unit determines, based on the information from the torque calculation unit, a stride for minimizing the root mean square value of the leg joint drive torque in accordance with the target speed. A second parameter generating unit that determines a stride that minimizes the maximum value of the leg joint drive torque in accordance with the generating unit or the target moving speed is selected, and based on the stride and the walking cycle from the selected parameter generating unit. The pattern generation unit generates a position control target value and outputs it to the joint control unit. In response to this, the joint control unit drives the leg mechanism. As a result, the maximum torque or the root mean square torque can be suppressed to the minimum value for maintaining the required moving speed, depending on the load condition of the actuator for driving the leg mechanism joint.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of a walking leg control device of the present invention. In this figure, 1 and 2 are leg mechanisms of a walking machine, and the leg mechanisms 1 and 2 are provided on a torso 3. . Leg mechanism described above
1 and 2 are the first joints 1A and 2A provided on the body 3, respectively,
First leg portions 1B and 2B connected to the first joint portions 1A and 2A,
Second joint portions 1C, 2C provided at the other ends of the first leg portions 1B, 2B
And the second leg 1D, 2D connected to the second joint 1C, 2C
And the third joints 1E, 2E connected to the second legs 1D, 2D
And foot portions 1F, 2F connected to the third joint portions 1E, 2E. In order to drive the leg mechanisms 1 and 2, actuators 1G, 2G, 1H and 2H are provided in the first joint portions 1A and 2A and the second joint portions 1C and 2C, respectively. Four
Is a speed command, 5 is a parameter generation unit, 6 is a pattern generation unit, and 7 is a joint control unit.

The speed command unit 4 described above determines the target moving speed V of the walking machine. For example, the parameter generation unit 5 including a memory circuit stores a step length S _m and a walking cycle τ _m that minimize the maximum leg joint drive torque during walking, which is uniquely determined corresponding to the target moving speed V, With respect to the input target moving speed V, the stride S _m and the walking cycle τ _m are output.

Next, the step length S _m and the walking cycle τ _m in the parameter generator 5
The setting of will be described in detail. FIG. 2 shows a movement form of the walking machine, and the walking machine walks by alternately moving the legs L represented by a solid line and a dashed line. The movement of one leg L is the stance phase WA (WA _{1 to} WA _{3 in the} figure) with the foot in contact with the ground, and the swing phase with the foot away from the ground.
It is divided into two exercises, WB (WB _{1 to} WB _{3 in the} figure)
Then, the mass of the body portion 3 is supported against gravity and moved forward, and in the swing phase WB, the leg portion L is swung forward in preparation for the movement in the next stance phase WA. In such a walking motion, the moving speed V is determined as follows by the repeating period of the walking motion, that is, the walking period τ and the step length S.

The driving torque T _t is the inertia torque T _j due to the angular acceleration of the joint as shown in the example of the leg joint driving torque waveform in FIGS. 3 to 5.
It can be regarded as a combined torque of the gravitational torque T _g due to the gravitational moment applied to the leg mechanism. As shown in FIG. 5, the gravitational torque T _g is dominant in the stance phase WA, and the maximum driving torque T _t1 at this time can be approximately expressed by the step S as follows.

T _t1 ≈ T _g max ≈ k ₁ S (2) where k _{1 is a} constant In addition, the inertia torque T _j shown in Fig. 4 becomes dominant in the swing phase WB, and the maximum drive torque T _t2 at this time is Can be approximately expressed from the stride S and the moving speed V as follows.

From the above, the maximum driving torque T _m can be expressed as follows, and as shown in FIG. 6, at each moving speed V, It has a minimum value with respect to the step length S.

Uniquely it is possible to obtain the optimum step length S _m of the maximum torque T _m minimization, as a function of the monovalent to the movement velocity V of the optimum step length S _m as shown in FIG. 7 with respect to the but connexion each moving speed V Can be set. In addition, the walking cycle τ _m is calculated from the equation (1). Can be defined as

Therefore, by storing the step length S _m and the walking period τ _m determined by the function shown in FIG. 7 and the equation (5) in the parameter generation unit 5 for each target speed V, the desired target moving speed V
On the other hand, the walking motion can be executed while keeping the maximum leg function driving torque at a minimum.

The pattern generation unit 6 includes a leg trajectory calculation unit 6A and a target joint angle calculation unit 6
It is composed of B and a phase conversion calculation unit 6C. The leg trajectory calculation unit 6A uses the step length S _m and the walking period τ _m as parameters, and based on the periodic function of the following equation, the first joint unit 1A of the leg mechanism 1
The position [X, Y] of the third joint 1E with respect to is calculated.

In addition, the target joint angle calculation unit 6B calculates the first joint unit 1A, the first joint unit 1A, the first joint unit 1A from the position [X, Y] of the third joint unit 1E based on the following equation determined by the geometric constraint condition of the leg mechanism 1. The target joint angles θ _R1 and θ _R2 of the second joint 1C are calculated.

Where l _{1 is} the length between the first joint 1A and the second joint 1C l _{2 is} the length between the second joint 1C and the third joint 1E The conversion calculation unit 6C calculates the target joint angles θ _r1 , θ _r2 , θ _r3, and θ _r4 of the leg mechanisms 1 and 2 from the target joint angles θ _R1 , θ _R2 and the walking cycle τ _m based on the following equation.

The joint control unit 7 includes the position control units 7A _{1 to} 7A ₄ and the driver 7B ₁
And a ~7B _4. The position control units 4a _{1 to} 4a ₄ are the target joint angles θ _{r1 to} θ _r4 obtained by the pattern generation unit and the joint angles θ detected by the joint angle detection sensors 1J, 1K and 2J, 2K of the leg mechanisms 1 and 2. _The respective deviations from ₁ , θ ₂ , θ ₃ and θ ₄ are calculated. The drivers 7B _{1 to} 7B ₄ output drive signals to the actuators 1G and 2G and 1H and 2H of the leg mechanisms 1 and 2 based on each deviation.

Next, the operation of the above-described embodiment of the apparatus of the present invention will be described.

When the target moving speed V is output from the speed command unit 4, the parameter generating unit 5 outputs the step length S _m and the walking cycle τ _m that minimize the maximum leg joint driving torque during walking in correspondence with the target moving speed V. To do. Based on the stride S _m and the walking cycle τ _m , the leg locus calculation unit 6A of the pattern generation unit 6 causes the third joint unit 1E to the first joint unit 1A of the leg mechanism 1.
The position [X, Y] of is calculated. Next, the target joint angle calculation unit 6B
Then, the joint angles θ _R1 and θ _R2 of the first joint 1A and the second joint 1C are calculated from the position [X, Y] of the third joint 1E. Further, the position conversion calculation unit 6C uses the target joint angles θ _R1 , θ _R2 and the walking cycle τ _m to determine the target joint angles of the first joints 1A, 2A and the second joints 1C, 2C of the leg mechanisms 1, 2. Calculate θ _r1 , θ _r2 and θ _r3 , θ _r4 . The target joint angles θ _r1 , θ _r2 , θ _r3 , and θ _r4 allow the joint control unit 7 to determine the joint angles θ ₁ , θ ₂ , and θ from the joint angle detection sensors 1J, 1K, 2J, and 2K.
A deviation from ₃ and θ ₄ is obtained, and a drive signal is output to the actuators 1G, 1H, 2G and 2H so that this deviation becomes zero. As a result, the actuators 1G, 1H, 2G, 2H will move to the target moving speed B.
On the other hand, a walking motion with a stride S _m and a walking cycle τ _m is performed. As a result, the leg joint drive torque of the leg mechanism in the walking machine can be suppressed to the minimum value for maintaining the required moving speed.

FIG. 8 shows another embodiment of the apparatus of the present invention, in which the same reference numerals as in FIG. 1 indicate the same parts. In the present embodiment, the parameter generating unit 5A stores and inputs the step length S _m and the walking period τ _a that minimize the root mean square leg joint drive torque during walking, which is uniquely determined corresponding to the target speed V. With respect to the target moving speed V, the step length S _a and the walking period τ _a
Is configured to output.

The root mean square torque T _a is approximately represented by the following equation.

Since the first integral term on the right side of the equation (8) is an increasing function and the second integral term on the right side is an decreasing function with respect to the stride S, as shown in FIG. 9, at each moving speed V, the root mean square torque is obtained.
T _a has _a minimum value with respect to the step length S. Therefore, the optimum stride S _a for minimizing the root mean square torque is uniquely set for each moving speed V.
The optimum stride S _a can be determined as a monovalent function with respect to the moving speed V as shown in FIG. Further, the walking cycle τ _a is calculated from the equation (1) as follows. Can be defined as

Therefore, according to this embodiment, by storing the step length S _a and the walking cycle τ _a determined by the function shown in FIG. 10 and the equation (9) in the parameter generation unit 5A for each target speed V,
The walking motion can be executed while keeping the root mean square leg joint drive torque at a minimum for an arbitrary target moving speed V.

In the parameter generator of the embodiment described above,
The walking cycle τ _m , τ _a uses the selected stride S _m , S _a ,
It is obvious that the method of directly calculating and outputting from the expressions (5) and (7) may be used.

Furthermore, although the above-described embodiment has been described with respect to the case where the leg mechanism has two legs, it can also be applied to a walking machine having several pairs of legs.

FIG. 11 shows still another embodiment of the walking leg control apparatus of the present invention, in which the same reference numerals as those in FIGS. 1 and 8 designate the same parts. Reference numerals 1 and 2 are leg mechanisms of the walking machine, and the leg mechanisms 1 and 2 are provided on the body 3. Each of the leg mechanisms 1 and 2 described above has a first joint portion 1 provided on the body portion 3, respectively.
A, 2A and the first leg 1 connected to the first joint 1A, 2A
B, 2B, second joint portions 1C, 2C provided at the other end of the first leg portions 1B, 2B, and second leg portions 1D, 2D connected to the second joint portions 1C, 2C And the third joint portions 1E, 2E connected to the second leg portions 1D, 2D, and the foot portion 1 connected to the third joint portions 1E, 2E
It is composed of F and 2F. In order to drive the leg mechanisms 1 and 2, the first joint portions 1A and 2A and the second joint portion 1 are driven.
Actuators 1G, 2G, 1H and 2H are provided in C and 2C, respectively. Torque sensors 1L, 1M and 2L, 2M are connected to the first joints 1A, 2A and the second joints 1C, 2C of the leg mechanisms 1, 2, respectively. 4 is a speed command unit, 50 is a first parameter generation unit, 60 is a second parameter generation unit, 70 is a torque calculation unit,
Reference numeral 80 is a parameter selection unit, 6 is a pattern generation unit, and 7 is a joint control unit.

The speed command unit 4 described above determines the target moving speed V of the walking machine. The first parameter generation unit 50 is composed of, for example, a memory circuit, stores the step length S _a that minimizes the root mean square value of the leg joint drive torque that is uniquely determined corresponding to the target moving speed V, and is input. Stride with respect to target moving speed V
Output S _a . The second parameter generation unit 60 is composed of, for example, a memory circuit, stores the step length S _m that minimizes the maximum value of the leg joint drive torque uniquely determined corresponding to the target moving speed V, and inputs it. Stride for target moving speed V
Output S _m .

Next, the above-mentioned first and second parameter generators 50, 60
The steps S _a and S _m in step S1 will be described in detail.

The setting of the step length S _{m is} the same as that of the above-described embodiment of the present invention, and the description thereof will be omitted.

Next, the setting of the step length S _a will be described. The root mean square value T _a of the leg joint drive torque is approximately represented by the following equation.

Since the first integral term on the right side of the equation (10) is an increasing function and the second integral term on the right side is an decreasing function with respect to the step length S, as shown in FIG. T _a has _a minimum value with respect to the step length S. Uniquely optimum step length S _a mean square torque minimization can be obtained, a function of the monovalent for optimal stride S _a moving speed V as shown in FIG. 10 described above were but against connexion each moving speed V Can be defined as

Next, returning to FIG. 11, the torque calculation unit 70 uses the torque sensors 1L, 1M and 2L, 2M connected to the first joints 1A, 2A and the second joints 1C, 2C of the leg mechanisms 1, 2, respectively. The maximum torque value T _m is calculated from the detected leg function driving torques T ₁ , T ₂ , T ₃ , T ₄ and the walking cycle τ calculated by the parameter generators 5, 6 based on the following equation.

T _m = MAX [max [T ₁ (τ)], max [T ₂ (τ)], [max [T ₃ (τ)], max [T ₄ (τ)]] (11) where: The parameter selection unit 80 includes a state determination unit 80A, a selection unit 80B and a synchronization calculation unit 80C. The state determination unit 80A compares the maximum torque value T _m obtained by the torque calculation unit 70 with a preliminarily stored allowable value T _mlim, and when T _m > T _mlim , the selection unit _80A.
Select stride S _m as a stride S to B, also gives an instruction to select stride S _a as stride length S in the case of _{T m} <T mlim.
The cycle calculator 80C calculates the walking cycle τ from the step S and the target moving speed V based on the following equation.

Next, the pattern generation unit 6 is composed of a leg locus calculation unit 6A, a target joint angle calculation unit 6B and a phase conversion calculation unit 6C as in the above-described embodiment. The leg trajectory calculation unit 6A calculates the position [X, Y] of the third joint 1E with respect to the first joint unit 1A of the leg mechanism 1 based on the periodic function of the following equation, using the stride S and the walking period τ as parameters. .

Further, the target joint angle calculation unit 6B calculates the first and second joint units 1A from the position [X, Y] of the third joint 1E based on the following equation determined by the geometric constraint condition of the leg mechanism 1. , 1C Target joint angles θ _R1 and θ _R2 are calculated.

Where l _{1 is} the length between the first joint 1A and the second joint 1C l _{2 is} the length between the second joint 1C and the third joint 1E The conversion calculation unit 6C calculates the target joint angles θ _r1 , θ _r2 , θ _r3, and θ _r4 of the leg mechanisms 1 and 2 from the target joint angles θ _R1 , θ _R2 and the walking cycle τ _m based on the following equation.

Further, the articulation control 7, and a position control unit 7A ₁ ~7A ₄ and driver 7B ₁ ~7B _4. Position controller 7A ₁ ~ 7A ₄
Is the target joint angle θ _{r1 to} θ obtained by the pattern generation unit 6.
The respective deviations of _r4 and the joint angles θ ₁ , θ ₂ , θ ₃ and θ ₄ detected by the joint angle detection sensors 1J, 1K and 2J, 2K of the leg mechanisms ₁ , ₂ are calculated. The drivers 7B _{1 to} 7B ₄ drive the actuators 1G, 1H and 2G, 2H of the leg mechanisms 1 and 2 based on each deviation.

According to the above configuration, when the leg mechanisms 1 and 2 have the same configuration, it is possible to realize the walking motion of the step S and the walking cycle τ with respect to the target of the moving speed V.

Next, the operation of another embodiment of the apparatus of the present invention described above will be described.

When the speed command unit 4 outputs the target moving speed V, the first parameter generating unit 50 calculates a stride S _a corresponding to the target moving speed V to minimize the root mean square value of the leg joint drive torque. In addition, the second parameter generator 60 sets the target moving speed V
Stride that minimizes the maximum value of the leg joint drive torque corresponding to
Calculate S _m . On the other hand, the torque calculation unit 7 is a torque sensor.
Leg joint drive torque T ₁ , T ₂ , T detected by 1L, 1M, 2L, 2M
_The maximum torque value T _m is calculated from ₃ and T ₄ and the walking cycle τ calculated by the parameter generation units 50 and 60, and is output to the state determination unit 80A of the parameter selection unit 80. As a result, the state determination unit 80A causes the maximum torque value T _m and the allowable value T _mlim stored in advance.
And in the case of T _m T _mlim , select the step S _m from the second parameter generator 6, and in the case of T _m T _mlim , select the step S _a from the first parameter generator 50. select. Further, the cycle calculator 80C calculates the walking cycle τ from the stride S and the target moving speed V. Next, in the pattern generation unit 6, the leg track calculation unit 6A uses the stride S and the walking period τ to determine the third joint 1E of the leg mechanism 1 with respect to the first joint 1A.
The position [X, Y] of is calculated. Next, the target joint angle calculator 6B calculates the target joint angles θ _R1 and θ _R2 of the first and second joints 1A and 1C based on the position [X, Y] of the third joint 1E. Next, the phase conversion calculation unit 6C determines the target joint angles θ _R1 , θ _R2.
And the walking cycle τ, the target joint angles θ _r1 ,
Calculate θ _r2 , θ _r3, and θ _r4 . The joint control unit 7 receives the target joint angles θ _r1 , θ _r2 , θ _r3 , and θ _r4 from the pattern generation unit 6 and the joint angles θ ₁ , θ ₂ , and θ detected by the joint angle detection sensors 1J, 1K and 2J, 2K. The deviations of ₃ and θ ₄ are obtained, and the actuators 1 and 2 of the leg mechanisms 1 and 2 are set so that the deviations become zero.
Drive signals are output to G, 1H and 2G, 2H. As a result, when the joint driving torque exceeds the maximum allowable value with respect to the target moving speed V, the maximum walking torque is minimized, and in other cases, the torque root mean square is minimized. Change the stride of. Thereby, the actuator for driving the leg mechanism can be controlled so as not to be overloaded, and the energy required for walking motion can be suppressed.

〔The invention's effect〕

According to the walking leg control apparatus of claim 1 of the present invention, the maximum value or the root mean square value of the leg joint driving torque of the walking machine can be suppressed to the minimum value for maintaining the required moving speed. The drive actuator can be made smaller and lighter, which is effective in reducing the weight of the walking machine as a whole.

According to the walking leg control device of claim 2 of the present invention, the maximum torque or the root mean square torque is set to the minimum value for maintaining the required moving speed in accordance with the load condition of the actuator for driving the leg joint in the walking machine. Since it can be suppressed, damage to the actuator due to overload can be prevented, energy consumption can be suppressed, and the actuator can be compact and compact.
By reducing the weight, the weight of the walking machine as a whole can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the device of the present invention, and FIG.
Explanatory diagram showing the walking motion of the leg machine, FIGS. 3 to 5 are diagrams showing the relationship between the torque acting on the leg and the walking cycle,
FIG. 6 is a diagram showing the relation between the stride and the maximum torque at each moving speed, FIG. 7 is a diagram showing the relation between the optimum stride and the moving speed, and FIG. 8 is a constitution of another embodiment of the device of the present invention. Figure, No. 9
Figure is a diagram showing the relationship between the step length and the walking cycle at each moving speed, FIG. 10 is a diagram showing the relationship between the step length and the moving speed, FIG. 11 is a block diagram of yet another embodiment of the device of the present invention. is there. 1,2 ...... Leg mechanism, 4 ... Speed command section, 5,5A ... Parameter generation section, 6 ... Pattern generation section, 7 ... Joint control section, 50
...... First parameter generation unit, 60 ...... Second parameter generation unit, 70 ...... Torque calculation unit, 80 ...... Parameter selection unit.

Front page continued (72) Inventor Yutaka Nakano 3-1-1, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Factory, Hitachi Factory Examiner Nobuo Fujimoto (56) References JP 62-97006 (JP, A) ) JP-A-62-187671 (JP, A)

Claims (2)

[Claims] 1. A walking control device for generating a motion pattern of a multi-joint leg mechanism of a walking mechanism, a speed command section for outputting a preset target moving speed, and a maximum driving torque of a leg joint with respect to the target moving speed. Function calculation function that calculates the stride and walking cycle to minimize the root mean square torque, or the maximum driving torque of the leg joint for multiple target moving speeds or the stride that minimizes the root mean square torque is specified as the memory and the stride. Calculation function that calculates the walking cycle from the target moving speed, or memory that stores the walking cycle that minimizes the maximum driving torque or the root mean square torque of the leg joint for multiple target moving speeds, and the target specified as the walking cycle A parameter that has a calculation function to calculate the stride from the moving speed and determines the stride and the walking cycle for the specified target moving speed. A raw part, a pattern generation part that generates a position control target value of the joint of the leg mechanism based on the determined stride length and a walking cycle, and a joint control part that controls the position of the joint of the leg mechanism based on the position control target value. A walking leg control device characterized by being provided. 2. A walking control device for generating a motion pattern of a multi-joint leg mechanism of a walking mechanism, wherein a speed command section for outputting a preset target moving speed and a root mean square torque of the leg joint with respect to the target moving speed. A function calculating function for calculating a stride to be minimized or a memory for storing a stride for minimizing the root mean square torque of a leg joint for a plurality of target moving speeds is provided, and a stride is determined for a specified target moving speed. Parameter generation unit and joint calculation function that calculates the stride that minimizes the maximum driving torque of the leg joint with respect to the target moving speed, or the memory that stores the stride that minimizes the maximum driving torque of the leg joint with respect to multiple target moving speeds And a second parameter generating section for determining a stride for a specified target moving speed, and a torque calculation for calculating the maximum value of the leg joint drive torque from the movement of the leg mechanism. When the maximum value of the leg joint drive torque exceeds a predetermined allowable value based on the information from the torque calculation unit, the stride output from the first parameter generation unit is selected, and the maximum value of the leg joint drive torque is A parameter selection unit that selects a stride output from the second parameter generation unit if the predetermined allowable value is not exceeded, and that calculates and outputs a walking cycle from a designated target moving speed and the selected stride, and a parameter selection unit. A pattern generation unit that generates a position control target value of the joint of the leg engine based on the stride and the walking cycle output from the above, and a joint control unit that controls the position of the joint of the leg mechanism based on the position control target value are provided. Walking leg control device characterized by.