A motion control system and method for an electric excavator actuator based on single handle operation

Abstract

The present invention proposes a motion control system and method for an electric-controlled excavator actuator based on single-handle operation. The system described in this scheme includes a flow optimization distribution algorithm running on an excavator controller, a four-dimensional single handle, a handle sensor, an actuator displacement sensor, and a sensor for measuring the hydraulic pressure of the actuator drive device; the operator controls the movement of the end of the actuator by operating the four-dimensional single handle, and the system optimization control algorithm based on kinematic / dynamic models and various constraints is responsible for converting the operator's action instructions into the movement of each actuator of the actuator, and controlling the movement of the pump and each valve, so as to realize the motion control of the excavator actuator.

Description

Technical Field

[0001] The invention relates to a motion control system and method of an electric-controlled excavator actuator based on single-handle operation, belonging to the technical field of mechanical control. Background Art

[0002] The current mainstream excavators adopt a man-in-the-loop overall control strategy. The action of each actuator of the excavator is realized by the driver directly issuing control signals (pilot pressure) through different operating levers according to the working conditions and his own experience. The man-in-the-loop overall control strategy has certain advantages. For example, a driver with rich operating experience can coordinate the movement of each actuator according to the task, action target and the understanding of the characteristics of the excavator being operated, and can complete the task more efficiently and flexibly under various working conditions. The disadvantage is that human perception and decision-making are usually not so accurate, so there is room for further optimization of their operation in terms of efficiency and energy consumption; in addition, it takes a long time for an excavator operator to reach the technical level of being able to operate the excavator flexibly and efficiently.

[0003] The existing mainstream excavators are operated by the driver to operate multiple handles, and control the movement of the valve core of the multi-way valve through the pilot oil circuit, and then control the flow of hydraulic oil to each actuator, thereby controlling the movement of each actuator.

[0004] The effect of the driver's complete and direct control over the movement of the excavator's actuators depends on the operator's personal experience and has large fluctuations. It is impossible to accurately optimize both the working speed and energy consumption. The operation is somewhat arbitrary, and it is difficult to achieve stable, continuous and smooth movements. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a motion control system and method for an electric-controlled excavator actuator based on single-handle operation, which can stably, continuously and smoothly control the actuator and avoid the operator's individual control of each valve core.

[0006] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a motion control system for an electric-controlled excavator actuator based on single-handle operation, the system comprising a controller and:

[0008] Four-dimensional single handle: used to express the excavator operator's motion instructions and form corresponding action information;

[0009] Handle sensor: used to collect the motion information of the four-dimensional single handle, and the controller converts it into the desired motion speed target of the end of the actuator;

[0010] Actuator displacement sensor: used to measure the configuration of each actuator, which is used to construct the inverse kinematics of the working device; the controller converts the desired motion speed target of the actuator end into the desired motion target of each actuator according to the pre-constructed inverse kinematics of the working device; the actuator inverse kinematics: converts the motion instruction information of the actuator end into the motion target of each actuator based on the current configuration;

[0011] Actuator pressure sensor: used to measure pressure; the pressure is used to construct a hydraulic system mathematical model; the controller generates the actuator's action target based on the pre-constructed hydraulic system mathematical model, the expected motion target of each actuator, and the optimal control target that takes into account work efficiency and energy consumption, combined with system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator.

[0012] Furthermore, the four-dimensional single handle has three degrees of freedom corresponding to the translation of the end of the excavator actuator and one degree of freedom corresponding to the rotation of the bucket shaft; the handle sensor is a displacement or force sensor.

[0013] Furthermore, if the motion of a certain actuator measured by the actuator sensor is close to the mechanical limit, its motion trajectory is replaced by the buffering motion instead of the expected motion obtained by the inverse kinematics solution.

[0014] Furthermore, the actuator includes a hydraulic actuator, and the hydraulic actuator includes a hydraulic cylinder and a hydraulic motor;

[0015] The action targets of the actuator include the flow rate of the hydraulic pump and the opening area of ​​the valve.

[0016] Furthermore, the hydraulic system mathematical model includes:

[0017]

[0018] Among them, x is a column vector, which contains the flow rate and flow derivative of each hydraulic cylinder and motor, A is the coefficient matrix, B is the control matrix, u is the control variable, including the flow rate of the hydraulic pump and the opening area of ​​each valve in the multi-way valve, and f is the external load and disturbance.

[0019] Furthermore, the optimal control objectives that take into account both work efficiency and energy consumption include:

[0020] J=K1×N+K2×abs(v-vq)

[0021] Where J is the optimization objective function, K1 is the energy consumption weight coefficient, N is the energy consumption value, K2 is the work efficiency weight coefficient, abs means taking the absolute value, v is the speed, and vq is the speed calculated based on the handle information.

[0022] Furthermore, the system constraints include:

[0023] Hydraulic pump capacity: minimum flow of hydraulic pump < flow of hydraulic pump < maximum flow of hydraulic pump;

[0024] Valve opening area: minimum valve opening area < valve opening area < maximum valve opening area.

[0025] In a second aspect, the present invention provides a motion control method for an electric-controlled excavator actuator based on single-handle operation, comprising the following steps:

[0026] Obtain the motion information of a four-dimensional single handle and convert it into the desired motion speed target at the end of the actuator;

[0027] According to the pre-built inverse kinematics of the working device, the desired motion speed target of the end of the actuator is converted into the desired motion target of each actuator; the inverse kinematics of the actuator: the motion instruction information of the end of the actuator is converted into the motion target of each actuator based on the current configuration;

[0028] According to the pre-constructed hydraulic system mathematical model, the expected motion targets of each actuator and the optimal control target that takes into account work efficiency and energy consumption, the action targets of the actuators are generated in combination with system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. Through four-dimensional single handle control, the automatic control system of the present invention can avoid the operator's individual control of each valve core, reducing the driver's labor intensity;

[0031] 2. The inverse kinematics of the actuator converts the end motion calculation of the actuator into the expected motion of each actuator, and combines the current configuration of the actuator and the buffer trajectory design to form the final motion speed target of each actuator, which is fast and accurate;

[0032] 3. The optimization algorithm based on the hydraulic system mathematical model and its constraints of the present invention determines the final motion target of each actuator, improves the overall operating efficiency and reduces energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1It is a flow chart of the control method of the present invention. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0035] Embodiment 1:

[0036] like Figure 1 As shown, this embodiment is a motion control system for an electric-controlled excavator actuator based on single-handle operation, and the system includes a controller and:

[0037] Four-dimensional single handle: used to express the excavator operator's motion instructions and form corresponding action information;

[0038] Handle sensor: used to collect the motion information of the four-dimensional single handle, and the controller converts it into the desired motion speed target of the end of the actuator;

[0039] Actuator displacement sensor: used to measure the configuration of each actuator, and the configuration is used to construct the inverse kinematics of the working device; the controller converts the desired motion speed target of the actuator end into the desired motion target of each actuator according to the pre-constructed inverse kinematics of the working device; the actuator inverse kinematics: converts the motion command information of the actuator end into the motion target of each actuator based on the current configuration; if the motion of a certain actuator measured by the actuator sensor is close to the mechanical limit, its motion trajectory is replaced by the buffer motion instead of the desired motion obtained by the inverse kinematics solution.

[0040] Inverse kinematics is a typical algorithm in robotics, and its basic form is:

[0041]

[0042] in, is the angular velocity of each actuator of the excavator corresponding to the terminal speed (vector, for the excavator, walking is not considered, including the rotation angular velocity of the bucket shaft, dipper arm shaft, boom shaft and turntable); J -1 is the inverse matrix of the Jacobian matrix of the actuator; θ is the current rotation angle of each axis; v is the desired motion speed of the end calculated by the handle sensor information. The specific expression is relatively complex and large, and has been described in the prior art, so it will not be described in detail in this embodiment.

[0043] Actuator pressure sensor: used to measure pressure; the pressure is used to construct a hydraulic system mathematical model; the controller generates the actuator's action target based on the pre-constructed hydraulic system mathematical model, the expected motion targets of each actuator, and the optimal control target that takes into account work efficiency and energy consumption, combined with system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator.

[0044] The four-dimensional single handle has three degrees of freedom corresponding to the translation of the end of the excavator actuator and one degree of freedom corresponding to the rotation of the bucket shaft; the inward and outward movement of the bucket have the same degree of freedom but in different directions, that is, different rotation directions of the bucket shaft can correspond to the inward or outward movement of the bucket.

[0045] The handle sensor is a displacement or force sensor.

[0046] The actuator is a hydraulic actuator, which includes a hydraulic cylinder and a hydraulic motor; the action targets of the actuator include the flow rate of the hydraulic pump and the opening area of ​​the valve.

[0047] The mathematical model of the hydraulic system is very complex, and its specific form depends on the specific topological configuration of the hydraulic system. Different product designs have different topological configurations, so the specific form and content of their mathematical models are also very different. For flow control, its mathematical model can be expressed in the following general form:

[0048]

[0049] Among them, x is a column vector, which includes the flow rate and flow derivative of each hydraulic cylinder and motor, A is the coefficient matrix, B is the control matrix, u is the control variable, including the flow rate of the hydraulic pump and the opening area of ​​each valve in the multi-way valve, and f is the external load and disturbance.

[0050] Specifically, the optimal control objectives that take into account both work efficiency and energy consumption include:

[0051] J=K1×N+K2×abs(v-vq)

[0052] Where J is the optimization objective function, K1 is the energy consumption weight coefficient, N is the energy consumption value, K2 is the work efficiency weight coefficient, abs(v-vq) means the absolute value of the difference between the optimized (angular) velocity v and the motion (angular) velocity vq calculated based on the handle information, v is the velocity, and vq is the velocity calculated based on the handle information.

[0053] System constraints include:

[0054] Hydraulic pump capacity: minimum flow of hydraulic pump < flow of hydraulic pump < maximum flow of hydraulic pump;

[0055] Valve opening area: minimum valve opening area < valve opening area < maximum valve opening area.

[0056] Embodiment 2:

[0057] This embodiment provides a motion control method for an electric-controlled excavator actuator based on single-handle operation, comprising the following steps:

[0058] Obtain the motion information of a four-dimensional single handle and convert it into the desired motion speed target at the end of the actuator;

[0059] According to the pre-built inverse kinematics of the working device, the desired motion speed target of the end of the actuator is converted into the desired motion target of each actuator; the inverse kinematics of the actuator: the motion instruction information of the end of the actuator is converted into the motion target of each actuator based on the current configuration;

[0060] According to the pre-constructed hydraulic system mathematical model, the desired motion targets of each actuator, and the optimal control target that takes into account work efficiency and energy consumption, the motion targets of the actuators are generated in combination with the system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator. In this technical solution, the operator controls the movement of the end of the actuator by operating the four-dimensional single handle. The system optimization control algorithm based on the kinematic / dynamic model and various constraints is responsible for converting the operator's action instructions into the movement of each actuator of the actuator, and controlling the movement of the pump and each valve to achieve the motion control of the excavator actuator.

[0061] The technician only needs to directly control the movement of the actuator end through a single operating handle, without having to control the movement of each actuator separately through multiple handles;

[0062] The optimal control algorithm realizes the control of the motion of each actuator, optimizing work efficiency and energy consumption;

[0063] Reduce the vibration of the actuator and make the movement smoother;

[0064] The force / displacement signal generated by the four-dimensional single handle is directly mapped to the movement of the end of the excavator's actuator, and the movement of the end of the excavator's actuator is directly controlled by the force / displacement signal generated by the four-dimensional single handle.

[0065] The motion generation method of each motion mechanism of the excavator integrates the operator's motion instructions, the inverse kinematics of the actuator, the limit protection motion trajectory and the optimization control algorithm.

[0066] Excavator actuator: refers to the excavator action realization mechanism including the swing motor, boom, dipper and bucket;

[0067] The actuators of the excavator: refers to the rotary motor or boom (cylinder) or arm (cylinder) or bucket (cylinder);

[0068] Four-dimensional single handle: an operating handle with four degrees of freedom that can directly control the movement of the end of the excavator's actuator. The displacement (or force) in three dimensions corresponds to the translational movement in the corresponding directions of the end of the actuator, and the other dimension corresponds to the inward (excavation) or outward (unloading) movement of the bucket.

[0069] Inverse kinematics of actuators: converting the motion command information of the actuator end into the motion target of each actuator based on the current configuration;

[0070] Hydraulic system dynamics model: the relationship between the input (pressure and flow at the pump end) and the output (pressure and flow at each actuator) in the hydraulic system.

[0071] The excavator operator determines the movement of the end of the working device according to the environment, the current position of the bucket and the task objectives, and expresses it through a four-dimensional single handle;

[0072] The relevant sensors (displacement or force sensors) collect the motion information of the four-dimensional handle and convert it into the desired motion speed target at the end of the actuator;

[0073] The sensor measures the configuration of the actuator and constructs the inverse kinematics of the working device;

[0074] The inverse kinematics of the actuator converts the desired motion speed target of the actuator end into the desired motion target of each actuator;

[0075] If the motion of a certain actuator measured by the sensor is close to the mechanical limit, its motion trajectory is replaced by the buffer motion instead of the expected motion obtained by the inverse kinematics solution;

[0076] The pressure measured by the pressure sensors at each hydraulic actuator (hydraulic cylinder, hydraulic motor) is used to build a mathematical model of the hydraulic system

[0077] Construct the optimal control target that takes into account both work efficiency and energy consumption, and generate the action targets of the hydraulic pump and each valve based on the system constraints.

[0078] The four-dimensional single handle corresponds to the three degrees of freedom of translation at the end of the excavator's actuator and one degree of freedom of rotation of the bucket's rotating shaft;

[0079] Automatic control strategy avoids the operator's individual control of each valve core;

[0080] The inverse kinematics of the actuator converts the end motion calculation of the actuator into the expected motion of each actuator, and forms the final motion speed target of each actuator in combination with the current configuration of the actuator and the buffer trajectory design;

[0081] The optimization algorithm based on the mathematical model of the hydraulic system and its constraints determines the final motion target of each actuator.

[0082] The undisclosed parts of this application are all prior art.

[0083] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0084] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0085] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0086] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A motion control system for an electric excavator actuator based on single handle operation, characterized in that: The system includes a controller and: Four-dimensional single handle: used to express the excavator operator's motion instructions and form corresponding action information; Handle sensor: used to collect the motion information of the four-dimensional single handle, and the controller converts it into the desired motion speed target of the end of the actuator; Actuator displacement sensor: used to measure the configuration of each actuator, which is used to construct the inverse kinematics of the working device; the controller converts the desired motion speed target of the actuator end into the desired motion target of each actuator according to the pre-constructed inverse kinematics of the working device; the actuator inverse kinematics: converts the motion instruction information of the actuator end into the motion target of each actuator based on the current configuration; Actuator pressure sensor: used to measure the hydraulic pressure of the actuator drive structure; the pressure is used to construct a hydraulic system mathematical model; the controller generates the actuator's motion target based on the pre-constructed hydraulic system mathematical model, the expected motion targets of each actuator, and the optimal control target that takes into account work efficiency and energy consumption, combined with system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator.

2. The motion control system of the electric excavator actuator based on single handle operation according to claim 1 is characterized in that: The four-dimensional single handle has three degrees of freedom corresponding to the translation of the end of the excavator actuator and one degree of freedom corresponding to the rotation of the bucket shaft; the rotation of the bucket includes the inward or outward rotation of the bucket; the handle sensor is a displacement or force sensor.

3. The motion control system of the electric excavator actuator based on single handle operation according to claim 1 is characterized in that: If the motion of an actuator measured by the actuator sensor is close to the mechanical limit, its motion trajectory is replaced by the buffer motion instead of the expected motion obtained by the inverse kinematics solution.

4. The motion control system of the electric excavator actuator based on single handle operation according to claim 1 is characterized in that: The actuator comprises a hydraulic actuator, and the hydraulic actuator comprises a hydraulic cylinder and a hydraulic motor; The action targets of the actuator include the flow rate of the hydraulic pump and the opening area of ​​the valve.

5. The motion control system of the electric excavator actuator based on single handle operation according to claim 1 is characterized in that: The mathematical model of the hydraulic system can be expressed as: Among them, x is a column vector, which contains the flow rate and flow derivative of each hydraulic cylinder and motor, A is the coefficient matrix, B is the control matrix, u is the control variable, including the flow rate of the hydraulic pump and the opening area of ​​each valve in the multi-way valve, and f is the external load and disturbance.

6. The motion control system of the electric excavator actuator based on single handle operation according to claim 1 is characterized in that: The optimal control objectives for both work efficiency and energy consumption include: J=K1×N+K2×abs(v-vq) Where J is the optimization objective function, K1 is the energy consumption weight coefficient, N is the energy consumption value of the hydraulic system in the actuator, K2 is the work efficiency weight coefficient, abs means taking the absolute value, v is the target speed, and vq is the speed calculated based on the handle information.

7. The motion control system of the electric excavator actuator based on single handle operation according to claim 1, characterized in that: The system constraints include: Hydraulic pump capacity: minimum flow of hydraulic pump < flow of hydraulic pump < maximum flow of hydraulic pump; Valve opening area: minimum valve opening area < valve opening area < maximum valve opening area.

8. A motion control method for an electric excavator actuator based on single handle operation, characterized in that: The following steps are involved: Obtain the motion information of a four-dimensional single handle and convert it into the desired motion speed target at the end of the actuator; According to the pre-built inverse kinematics of the working device, the desired motion speed target of the end of the actuator is converted into the desired motion target of each actuator; the inverse kinematics of the actuator: the motion instruction information of the end of the actuator is converted into the motion target of each actuator based on the current configuration; According to the pre-constructed hydraulic system mathematical model, the expected motion targets of each actuator, and the optimal control target that takes into account work efficiency and energy consumption, the action targets of the actuators are generated in combination with system constraints; the hydraulic system dynamics model is the relationship between input and output in the hydraulic system; the hydraulic system input includes the pressure and flow at the pump end; the hydraulic system output includes the pressure and flow at each actuator.

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