Mobile robot motion control method with dynamic acceleration and deceleration constraints

Abstract

The invention belongs to the field of mobile robot motion control, and relates to a dynamic acceleration and deceleration constrained mobile robot motion control method. Comprising the steps of parameter initialization, acceleration and deceleration curve modeling, dynamic curve adjustment and control output constraint. According to the method, by introducing an acceleration and deceleration staged model of in-situ rotation control and walking control and combining external control signals, environment feedback and curvature changes of a path, an acceleration and deceleration curve is dynamically adjusted, smooth transition and intelligent adjustment of the linear speed and the angular speed of the mobile robot in the path execution process are achieved, and the path execution efficiency is improved. The path tracking precision, the control robustness and the intelligence and safety level of the whole motion control system are obviously improved.

Description

Technical Field

[0001] The invention belongs to the field of mobile robot motion control and relates to a mobile robot motion control method with dynamic acceleration and deceleration constraints. Background Art

[0002] In recent years, with the rapid development of artificial intelligence, industrial automation, and mobile communications technologies, advanced equipment, such as intelligent mobile robots, has gradually penetrated from the laboratory into practical applications. This type of intelligent equipment has demonstrated significant application value in a wide range of fields, including healthcare, education and training, service industries, warehousing and logistics, and industrial manufacturing. It effectively reduces labor costs, improves production efficiency, and enhances the quality of life, possessing significant social and economic significance.

[0003] In the actual engineering applications of mobile robots, the dynamic response performance of the motion control algorithm directly determines the overall operating efficiency and stability of the system. In particular, the reasonable setting of acceleration parameters requires a delicate balance between the device's response speed and motion smoothness. Excessive acceleration may cause severe impact on the mechanical body, reduce equipment stability and pose a safety hazard; conversely, too low acceleration will make it difficult to meet the rigid requirements of industrial scenarios for operational efficiency. In addition, mobile robots will inevitably encounter various operating conditions during actual operation. For example, they need to slow down and avoid obstacles in front of them, stop quickly in emergencies, decelerate smoothly when pausing a task, and accelerate gradually when resuming a task.

[0004] In warehousing and handling applications, mobile robots require smooth acceleration and deceleration control to ensure operational safety and precision. Due to the varying performance of motors in different vehicle models, robots experience varying responsiveness to angular and linear speeds as they approach a target cargo location or station. Traditional methods of reducing angular or linear speeds to extremely low values ​​can cause some robots to stop due to inability to respond, preventing the task from being completed. Similarly, controlling angular or linear speeds by dropping directly from high speed to extremely low speeds or making an emergency stop can not only affect positioning accuracy but can also adversely affect cargo stability and system lifespan.

[0005] Chinese patent publication number CN117519205A: A method for accelerating and decelerating a mobile robot. This technical solution is to calculate the difference between the current linear velocity of the mobile robot and the linear velocity of the next moment, and then based on the difference, correct the linear velocity of the next moment and adaptively correct the angular velocity of the next moment. According to the changes in the linear velocity and angular velocity of the mobile robot before and after, the output value of the response at the next moment is dynamically changed. Under the premise of ensuring the smooth movement of the vehicle body, the robot is ensured to travel along the original driving trajectory as much as possible, thereby improving the safety performance and control system of the mobile robot. This method performs an acceleration and deceleration process on the speed difference between the front and back, and corrects the linear velocity and angular velocity values ​​of the mobile robot without changing the control radius. What changes is the control amount result of the tracking path, which will change the target effect of path tracking.

[0006] Chinese patent publication number CN119575974A: Speed ​​planning method, device, equipment, and storage medium for mobile robots. This technical solution divides the movement process of the mobile robot from the starting point to the end point into multiple stages, avoiding acceleration jumps, effectively increasing the service life of the mobile robot and reducing the failure rate. In addition, a corresponding relationship between displacement and speed is established, so that the speed of the mobile robot's movement process can be directly controlled based on this corresponding relationship without complex calculations, allowing even a microcontroller with average performance to achieve smooth and efficient acceleration and deceleration control. However, this method does not take into account the smooth control of angular velocity when the rotational speed is zero.

[0007] In view of the above complex working conditions, how to construct an acceleration and deceleration curve with continuous and diffractive characteristics to ensure a smooth transition of the motion state and achieve a smooth start without shock has important engineering value for extending the life of the machinery and ensuring operational safety. Summary of the Invention

[0008] To address these issues, the present invention provides a mobile robot motion control method with dynamic acceleration and deceleration constraints. Within a certain range from the target position, the robot automatically enters a deceleration phase, maintaining a low, controllable speed and coming to a steady stop. This method balances control accuracy with motor responsiveness, preventing loss of control or slippage caused by excessive deceleration. Furthermore, except in emergencies, the mobile robot avoids drastic acceleration and deceleration throughout its operation, ensuring cargo safety, equipment durability, and improving overall operational efficiency.

[0009] The technical solution adopted by the present invention to achieve the above-mentioned object is: a mobile robot motion control method with dynamic acceleration and deceleration constraints, comprising the following steps:

[0010] S1. Parameter initialization: Set the acceleration and deceleration parameters of rotation control and walking control to provide basic configuration for subsequent modeling;

[0011] S2. Acceleration and deceleration curve modeling: Construct an acceleration and deceleration gradient curve model to describe the dynamic characteristics of the robot during speed changes;

[0012] S3, dynamic curve adjustment: According to external control signals or environmental feedback, the parameter values ​​in the curve model are adjusted in real time to achieve dynamic optimization of the acceleration and deceleration process;

[0013] S4. Control output constraint: The adjusted acceleration and deceleration control values ​​are used as constraint inputs and provided to the path tracking module to ensure that the robot runs smoothly and accurately during the path execution process.

[0014] In step S1, the in-situ rotation control refers to the scenario in which the mobile robot adjusts its orientation in-situ, including direction calibration before starting, angle adjustment after the task is completed, and execution of angle rotation operations in response to external commands; its control includes: a rotation acceleration stage, that is, gradually increasing the angular velocity from a stationary state to avoid sudden changes in angular velocity causing unstable posture or decreased control accuracy; a uniform rotation stage, that is, maintaining a constant angular velocity during the rotation process to achieve high-speed and stable angle adjustment; a rotation deceleration stage, that is, gradually reducing the angular velocity when approaching the target angular velocity to prevent overshoot and improve angle control accuracy.

[0015] The acceleration and deceleration parameter settings for the in-situ rotation control include the following angular velocity control parameter settings:

[0016] (1) Set the maximum angular velocity ω1, in rad / s, to limit the maximum angular velocity of the mobile robot during rotation;

[0017] (2) Set the angular acceleration α1, unit rad / s 2 , used to control the acceleration process of angular velocity from zero to maximum value;

[0018] (3) Set the angular deceleration α2, unit rad / s 2 , used for smooth deceleration when approaching the target speed;

[0019] (4) Set the minimum effective angular velocity ω2, in rad / s, to prevent the actuator from failing to respond due to the angular velocity being too low in the low-speed stage;

[0020] (5) Set the stop judgment threshold θ1, in rad, that is, when the difference between the orientation and the target orientation is less than this value, the task rotation task is completed;

[0021] (6) Set the robot’s control period to t, in seconds.

[0022] In step S2, the construction of the acceleration / deceleration gradient curve model includes a rotation acceleration / deceleration gradient curve model that describes the dynamic characteristics of the angular velocity of the robot during the rotation process. The rotation acceleration / deceleration gradient curve model includes:

[0023] When entering the control process for the first time or when the external setting resets the angular velocity, initialize the angular velocity ω of the previous moment p =0, and reset the deceleration state to false;

[0024] According to the robot's current orientation θ r With the target heading θ p The angle difference Δθ between them is Δθ=θ r -θ p If Δθ>0, it means the vehicle needs to rotate to the left. On the contrary, if Δθ<0, it means the vehicle needs to rotate to the right. The rotation direction of the vehicle follows the right-hand rule. When |Δθ|<θ1, it is determined that the angular velocity has reached the set threshold, the rotation task is completed, the output angular velocity is zero, and the control ends.

[0025] The acceleration phase of the mobile robot is:

[0026] ω=min((ω p +α1*t),w1)

[0027] Using the above accelerated ω, the angle value that needs to be decelerated during rotation is calculated in real time When the remaining angle difference |Δθ|<θ brake When the vehicle enters the deceleration braking process, that is, ω=ω p -α2*t;

[0028] The deceleration braking process is as follows: once the robot enters the deceleration process and the deceleration state is set to true, the robot will continue to decelerate until the minimum effective angular velocity ω2 is reduced and the remaining angle meets the stop judgment threshold, and the rotation action is completed.

[0029] In step S1, the walking control refers to the speed control used for the robot in a moving state during path tracking, handling operations, etc., and the control includes: the acceleration stage, that is, gradually increasing the linear speed from the starting state to enable the robot to smoothly enter the path tracking state; the uniform speed stage, in the middle section of the path or on a straight path, the linear speed is stable in position to achieve efficient walking behavior; the deceleration stage, that is, when approaching the target position or when it is necessary to stop the operation, the linear speed is gradually reduced to ensure that the vehicle body stops smoothly, improve positioning accuracy and ensure the safety of the goods.

[0030] The acceleration and deceleration parameter settings of the walking control include the settings of the following speed control parameters:

[0031] (1) Set the maximum linear velocity V1, in m / s, to limit the maximum speed of the robot during driving;

[0032] (2) Set the linear acceleration to A1, unit m / s 2 , used to control the acceleration process of the robot from a stationary state to the maximum travel speed, ensuring that the acceleration process is smooth and controlled;

[0033] (3) Set the linear deceleration to A2, unit: m / s 2 , used to control the robot to slow down and stop when approaching the target point, to avoid exceeding the target position due to insufficient braking distance;

[0034] (4) Set the minimum linear velocity to V2, in m / s, to prevent the driver from not responding or the vehicle from not moving due to the linear velocity being too low during low-speed driving, and to ensure effective movement during fine control.

[0035] (5) Set the low-speed switching distance threshold to D1, in meters, to determine whether the distance between the robot and the target point enters the low-speed driving area. When the remaining distance is less than D1, the mobile robot will maintain the minimum linear speed V2.

[0036] (6) Set the stopping distance to D2, in meters, to determine whether the vehicle has reached the task point;

[0037] (7) Set the minimum turning speed to V3, in m / s, to keep the vehicle in a controllable state when the robot is in the turning or low-speed movement stage, and avoid dead zones or slipping in place.

[0038] In step S2, the construction of the acceleration / deceleration gradient curve model includes a walking acceleration / deceleration gradient curve model that describes the dynamic characteristics of the linear velocity of the robot during walking. The walking acceleration / deceleration gradient curve model includes:

[0039] When entering the control process for the first time or when the external setting resets the angular velocity, initialize the linear velocity V at the previous moment P = 0, and reset the deceleration state to false; if the robot meets the conditions for reaching the target point, the walking task is completed;

[0040] The acceleration phase of the mobile robot is:

[0041] V=min((V p +A1*t),V1)

[0042] Using the accelerated V above, calculate the distance you need to decelerate while walking in real time When the distance between the robot and the target point |ΔL| <L brakeWhen the vehicle enters the deceleration braking process, that is: V=V p -A2*t;

[0043] When the robot is in the acceleration stage or the uniform speed stage, when there is a curve with a large curvature on the path, if the robot continues to maintain a high linear speed, the path tracking accuracy will decrease. Therefore, the output linear speed value of the robot is constrained based on the real-time curvature value of the path. Assuming that the calculated curvature speed is V cur , the final output control speed is:

[0044] V=min(V cur , V);

[0045] The curvature velocity calculation method includes:

[0046] The path to be tracked is segmented offline according to the preset map resolution m to obtain a sequence of path points;

[0047] Get the index of the nearest path point corresponding to the current posture of the robot. Starting from this index point, search for (K1*V1) / m path points in the front of the path and (K2*V1) / m path points in the back of the path, where K1 and K2 are preset constants and m is the map resolution. The forward path point set and the backward path point set together constitute the path sampling set.

[0048] Calculate the slope angle between adjacent path points in the path sampling set. The calculation formula of the slope angle θ is:

[0049]

[0050] Among them, (x2, y2) and (x1, y1) are the coordinates of two adjacent path points;

[0051] Accumulate the slope angles of all adjacent points in the path sampling set and add the accumulated values Set to no more than π;

[0052] Add the accumulated value Bring in the high-speed function for calculating the curvature coefficient to get the curvature coefficient. The smaller the value, the flatter the path. When the value is zero, it means that the straight line path set is being tracked at this moment. Define the input but

[0053]

[0054] like , further adjusted to:

[0055]

[0056] Then the curvature velocity at the current moment is:

[0057] The judgment of whether the vehicle has reached the task point is to solve the problem that the mobile robot cannot accurately stop at the target point due to inertial slip or navigation error, and no longer directly use the robot's terminal target posture M (x m ,y m ,θ m ) as the parking decision point, but introduces a parking control extension point N(x n ,y n ,θ n ), which is obtained by extending the target posture along its direction by a distance D2. The calculation method of the reference control point N is:

[0058]

[0059] Among them: D2>0 means early parking, the robot will stop before the target point; D2=0 means strictly parking at the target point; D2<0 means the robot will stop after passing the target;

[0060] A task reference line segment is constructed between the target point M and the extension point N, and a normal judgment line perpendicular to the direction of the line segment is constructed at point N as the boundary for whether the task point has been reached: when the robot's real-time position and the position L meters in front of the target point are on one side of the normal judgment line, it means that the robot has not reached the target point and needs to continue walking; when they are on both sides of the normal judgment line, it means that the robot has reached the target point and the walking task is completed, and the said L>|D2|.

[0061] In step S3, the external control signal or environmental feedback signal includes one or more of the following situations:

[0062] When the vehicle encounters an obstacle in front of it during its travel, it needs to reduce its travel speed. The travel acceleration and deceleration module will automatically reduce the maximum linear speed parameter.

[0063] When the external system issues a pause command, the deceleration parameter will be increased and the target point position will be advanced, so that the speed of the mobile robot will be reduced to zero faster;

[0064] When an obstacle is encountered abnormally or the vehicle is in a paused state, the maximum linear speed is restored to the value in the preset configuration parameters.

[0065] The external control signal immediately reduces the angular velocity and / or linear velocity of the vehicle to zero in the event of an emergency, such as when the emergency stop button is pressed, the anti-collision bar is triggered, or the obstacle avoidance radar detects a close obstacle;

[0066] After the above danger is eliminated, the vehicle body gradually accelerates from zero to the maximum speed at a preset acceleration.

[0067] In step S4, the path tracking module includes but is not limited to tracking control and nonlinear control.

[0068] Building on the aforementioned acceleration and deceleration curve model, an adaptive speed control mechanism based on path prediction or machine learning can be further introduced. Specifically, deep reinforcement learning or model predictive control methods can be used to dynamically generate optimized acceleration and deceleration control strategies, leveraging the robot's current position, the local curvature of the planned path, obstacle distribution, and historical motion data. This approach, while maintaining real-time response and safety, further improves the ability to balance path execution efficiency and energy consumption control in complex dynamic environments.

[0069] The present invention introduces a staged acceleration and deceleration model for rotation control and walking control, combines external control signals, environmental feedback, and changes in path curvature, and dynamically adjusts the acceleration and deceleration curves, achieving smooth transitions and intelligent regulation of the linear and angular velocities of the mobile robot during path execution. The system can flexibly adjust the acceleration and deceleration rhythm according to the straight or curved characteristics of the path, improving operational stability and control accuracy in turning areas. At the same time, it can quickly respond and safely decelerate when obstacles are detected or external commands such as emergency stops are received, significantly enhancing safety and environmental adaptability during operation. In addition, by introducing a delayed parking determination strategy, the present invention no longer relies solely on the distance between the vehicle body posture and the navigation target posture when determining whether the robot has reached the task point. Instead, it constructs a control area and normal boundary line at a certain distance in front of the target point to achieve accurate determination of the arrival status, effectively solving the problem of parking deviation caused by inertial slip or navigation errors, and further improving positioning accuracy and task completion reliability. In summary, the present invention significantly improves path tracking accuracy, control robustness, and the intelligence and safety level of the entire motion control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 This is the acceleration and deceleration constraint module diagram of the present invention.

[0071] Figure 2 Schematic diagram for determining the arrival at the target point. DETAILED DESCRIPTION

[0072] The following is a further description of this patent with reference to the accompanying drawings and specific embodiments:

[0073] Example

[0074] like Figure 1 A mobile robot motion control method with dynamic acceleration and deceleration constraints is shown, comprising the following steps:

[0075] S1. Parameter initialization: Set the acceleration and deceleration parameters of rotation control and walking control to provide basic configuration for subsequent modeling;

[0076] S2. Acceleration and deceleration curve modeling: Construct an acceleration and deceleration gradient curve model to describe the dynamic characteristics of the robot during speed changes;

[0077] S3, dynamic curve adjustment: According to external control signals or environmental feedback, the parameter values ​​in the curve model are adjusted in real time to achieve dynamic optimization of the acceleration and deceleration process;

[0078] S4. Control output constraint: The adjusted acceleration and deceleration control values ​​are used as constraint inputs and provided to the path tracking module to ensure that the robot runs smoothly and accurately during the path execution process.

[0079] In step S1, the in-situ rotation control refers to the scenario in which the mobile robot adjusts its orientation in-situ, including direction calibration before starting, angle adjustment after the task is completed, and execution of angle rotation operations in response to external commands; its control includes: a rotation acceleration stage, that is, gradually increasing the angular velocity from a stationary state to avoid sudden changes in angular velocity causing unstable posture or decreased control accuracy; a uniform rotation stage, that is, maintaining a constant angular velocity during the rotation process to achieve high-speed and stable angle adjustment; a rotation deceleration stage, that is, gradually reducing the angular velocity when approaching the target angular velocity to prevent overshoot and improve angle control accuracy.

[0080] The acceleration and deceleration parameter settings for the in-situ rotation control include the following angular velocity control parameter settings:

[0081] (1) Set the maximum angular velocity ω1, in rad / s, to limit the maximum angular velocity of the mobile robot during rotation;

[0082] (2) Set the angular acceleration α1, unit rad / s 2 , used to control the acceleration process of angular velocity from zero to maximum value;

[0083] (3) Set the angular deceleration α2, unit rad / s 2 , used for smooth deceleration when approaching the target speed;

[0084] (4) Set the minimum effective angular velocity ω2, in rad / s, to prevent the actuator from failing to respond due to the angular velocity being too low in the low-speed stage;

[0085] (5) Set the stop judgment threshold θ1, in rad, that is, when the difference between the orientation and the target orientation is less than this value, the task rotation task is completed;

[0086] (6) Set the robot’s control period to t, in seconds.

[0087] In step S2, the construction of the acceleration / deceleration gradient curve model includes a rotation acceleration / deceleration gradient curve model that describes the dynamic characteristics of the angular velocity of the robot during the rotation process. The rotation acceleration / deceleration gradient curve model includes:

[0088] When entering the control process for the first time or when the external setting resets the angular velocity, initialize the angular velocity ω of the previous moment p =0, and reset the deceleration state to false;

[0089] According to the robot's current orientation θ r With the target heading θ p The angle difference between them is Δθ, Δθ = θ r -θ p If Δθ>0, it means the vehicle needs to rotate to the left. On the contrary, if Δθ<0, it means the vehicle needs to rotate to the right. The rotation direction of the vehicle follows the right-hand rule. When |Δθ|<θ1, it is determined that the angular velocity has reached the set threshold, the rotation task is completed, the output angular velocity is zero, and the control ends.

[0090] The acceleration phase of the mobile robot is:

[0091] ω=min((ω p +α1*t),w1)

[0092] Using the above accelerated ω, the angle value that needs to be decelerated during rotation is calculated in real time When the remaining angle difference |Δθ|<θ brake When the vehicle enters the deceleration braking process, that is, ω=ω p -α2*t;

[0093] The deceleration braking process is as follows: once the robot enters the deceleration process and the deceleration state is set to true, the robot will continue to decelerate until the minimum effective angular velocity ω2 is reduced and the remaining angle meets the stop judgment threshold, and the rotation action is completed.

[0094] In step S1, the walking control refers to the speed control used for the robot in a moving state during path tracking, handling operations, etc., and the control includes: the acceleration stage, that is, gradually increasing the linear speed from the starting state to enable the robot to smoothly enter the path tracking state; the uniform speed stage, in the middle section of the path or on a straight path, the linear speed is stable in position to achieve efficient walking behavior; the deceleration stage, that is, when approaching the target position or when it is necessary to stop the operation, the linear speed is gradually reduced to ensure that the vehicle body stops smoothly, improve positioning accuracy and ensure the safety of the goods.

[0095] The acceleration and deceleration parameter settings of the walking control include the settings of the following speed control parameters:

[0096] (1) Set the maximum linear velocity V1, in m / s, to limit the maximum speed of the robot during driving;

[0097] (2) Set the linear acceleration to A1, unit: m / s 2 , used to control the acceleration process of the robot from a stationary state to the maximum travel speed, ensuring that the acceleration process is smooth and controlled;

[0098] (3) Set the linear deceleration to A2, unit: m / s 2 , used to control the robot to slow down and stop when approaching the target point, to avoid exceeding the target position due to insufficient braking distance;

[0099] (4) Set the minimum linear velocity to V2, in m / s, to prevent the driver from not responding or the vehicle from not moving due to the linear velocity being too low during low-speed driving, and to ensure effective movement during fine control.

[0100] (5) Set the low-speed switching distance threshold to D1, in meters, to determine whether the distance between the robot and the target point enters the low-speed driving area. When the remaining distance is less than D1, the mobile robot will maintain the minimum linear speed V2.

[0101] (6) Set the stopping distance to D2, in meters, to determine whether the vehicle has reached the task point;

[0102] (7) Set the minimum turning speed to V3, in m / s, to keep the vehicle in a controllable state when the robot is in the turning or low-speed movement stage, and avoid dead zones or slipping in place.

[0103] In step S2, the construction of the acceleration / deceleration gradient curve model includes a walking acceleration / deceleration gradient curve model that describes the dynamic characteristics of the linear velocity of the robot during walking. The walking acceleration / deceleration gradient curve model includes:

[0104] When entering the control process for the first time or when the external setting resets the angular velocity, initialize the linear velocity V at the previous moment P = 0, and reset the deceleration state to false; if the robot meets the conditions for reaching the target point, the walking task is completed;

[0105] The acceleration phase of the mobile robot is:

[0106] V=min((V p +A1*t),V1)

[0107] Using the accelerated V above, calculate the distance you need to decelerate while walking in real time When the distance between the robot and the target point |ΔL|<L brakeWhen the vehicle enters the deceleration braking process, that is: V=V p -A2*t;

[0108] When the robot is in the acceleration stage or the uniform speed stage, when there is a curve with a large curvature on the path, if the robot continues to maintain a high linear speed, the path tracking accuracy will decrease. Therefore, the output linear speed value of the robot is constrained based on the real-time curvature value of the path. Assuming that the calculated curvature speed is V cur , the final output control speed is:

[0109] V=min(V cur , V);

[0110] The curvature velocity calculation method includes:

[0111] The path to be tracked is segmented offline according to the preset map resolution m to obtain a sequence of path points;

[0112] Get the index of the nearest path point corresponding to the current posture of the robot. Starting from this index point, search for (K1*V1) / m path points in the front of the path and (K2*V1) / m path points in the back of the path, where K1 and K2 are preset constants and m is the map resolution. The forward path point set and the backward path point set together constitute the path sampling set.

[0113] Calculate the slope angle between adjacent path points in the path sampling set. The calculation formula of the slope angle θ is:

[0114] Among them, (x2, y2) and (x1, y1) are the coordinates of two adjacent path points;

[0115] Accumulate the slope angles of all adjacent points in the path sampling set and add the accumulated values Set to no more than π;

[0116] The accumulated value Bring in the high-speed function for calculating the curvature coefficient to get the curvature coefficient. The smaller the value, the flatter the path. When the value is zero, it means that the straight line path set is being tracked at this moment. Define the input but

[0117]

[0118] like , further adjusted to:

[0119]

[0120] Then the curvature velocity at the current moment is:

[0121] The judgment of whether the vehicle has reached the task point is to solve the problem that the mobile robot cannot accurately stop at the target point due to inertial slip or navigation error, and no longer directly use the robot's terminal target posture M (x m ,y m ,θ m ) as the parking decision point, but introduces a parking control extension point N(x n ,y n ,θ n ), which is obtained by extending the target posture along its direction by a distance D2. The calculation method of the reference control point N is:

[0122]

[0123] Among them: D2>0 means early parking, the robot will stop before the target point; D2=0 means strictly parking at the target point; D2<0 means the robot will stop after passing the target;

[0124] like Figure 2 As shown, a task reference line segment is constructed between the target point M and the extension point N, and a normal judgment line perpendicular to the line segment direction is constructed at point N as the boundary for whether the task point has been reached: when the robot's real-time position and the position L meters in front of the target point are on one side of the normal judgment line, it means that the robot has not reached the target point and needs to continue walking; when they are on both sides of the normal judgment line, it means that the robot has reached the target point and the walking task is completed, and the said L>|D2|.

[0125] In step S3, the external control signal or environmental feedback signal includes one or more of the following situations:

[0126] When the vehicle encounters an obstacle in front of it during its travel, it needs to reduce its travel speed. The travel acceleration and deceleration module will automatically reduce the maximum linear speed parameter.

[0127] When the external system issues a pause command, the deceleration parameter will be increased and the target point position will be advanced, so that the speed of the mobile robot will be reduced to zero faster;

[0128] When an obstacle is encountered abnormally or the vehicle is in a paused state, the maximum linear speed is restored to the value in the preset configuration parameters.

[0129] The external control signal immediately reduces the angular velocity and / or linear velocity of the vehicle to zero in the event of an emergency, such as when the emergency stop button is pressed, the anti-collision bar is triggered, or the obstacle avoidance radar detects a close obstacle;

[0130] After the above danger is eliminated, the vehicle body gradually accelerates from zero to the maximum speed at a preset acceleration.

[0131] In step S4, the path tracking module includes but is not limited to tracking control and nonlinear control.

Claims

1. A mobile robot motion control method with dynamic acceleration and deceleration constraints, characterized by: The following steps are involved: S1. Parameter initialization: Set the acceleration and deceleration parameters of rotation control and walking control to provide basic configuration for subsequent modeling; S2. Acceleration and deceleration curve modeling: Construct an acceleration and deceleration gradient curve model to describe the dynamic characteristics of the robot during speed changes; S3, dynamic curve adjustment: According to external control signals or environmental feedback, the parameter values ​​in the curve model are adjusted in real time to achieve dynamic optimization of the acceleration and deceleration process; S4. Control output constraint: The adjusted acceleration and deceleration control values ​​are used as constraint inputs and provided to the path tracking module to ensure that the robot runs smoothly and accurately during the path execution process.

2. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1, wherein: In step S1, the in-situ rotation control refers to the scenario where the mobile robot adjusts its orientation in-situ, including direction calibration before starting, angle adjustment after the task is completed, and execution angle rotation operations in response to external commands; Its control includes: the rotation acceleration stage, that is, gradually increasing the angular velocity from a stationary state to avoid sudden changes in angular velocity causing unstable posture or decreased control accuracy; The uniform rotation stage is to maintain a constant angular velocity during the rotation process to achieve high-speed and stable angle adjustment; the deceleration stage is to gradually reduce the angular velocity when approaching the target angular velocity to prevent overshoot and improve the angle control accuracy.

3. A method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1 or 2, characterized in that: The acceleration and deceleration parameter settings for the in-situ rotation control include the following angular velocity control parameter settings: (1) Set the maximum angular velocity ω1, in rad / s, to limit the maximum angular velocity of the mobile robot during rotation; (2) Set the angular acceleration α1, unit rad / s 2 , used to control the acceleration process of angular velocity from zero to maximum value; (3) Set the angular deceleration α2, unit rad / s 2 , used for smooth deceleration when approaching the target speed; (4) Set the minimum effective angular velocity ω2, in rad / s, to prevent the actuator from failing to respond due to the angular velocity being too low in the low-speed stage; (5) Set the stop judgment threshold θ1, in rad, that is, when the difference between the orientation and the target orientation is less than this value, the task rotation task is completed; (6) Set the robot’s control period to t, in seconds.

4. A mobile robot motion control method with dynamic acceleration and deceleration constraints according to claim 1 or 2, characterized in that: In step S2, the construction of the acceleration / deceleration gradient curve model includes a rotation acceleration / deceleration gradient curve model that describes the dynamic characteristics of the angular velocity of the robot during the rotation process. The rotation acceleration / deceleration gradient curve model includes: When entering the control process for the first time or when the external setting resets the angular velocity, initialize the angular velocity ω of the previous moment p =0, and reset the deceleration state to false; According to the robot's current orientation θ r With the target heading θ p The angle difference Δθ between them is Δθ=θ r -θ p If Δθ>0, it means the vehicle needs to rotate to the left. On the contrary, if Δθ<0, it means the vehicle needs to rotate to the right. The rotation direction of the vehicle follows the right-hand rule. When |Δθ|<θ1, it is determined that the angular velocity has reached the set threshold, the rotation task is completed, the output angular velocity is zero, and the control ends. The acceleration phase of the mobile robot is: ω=min((ω p +α1*t),w1) Using the above accelerated ω, the angle value that needs to be decelerated during rotation is calculated in real time When the remaining angle difference |Δθ|<θ brake When the vehicle enters the deceleration braking process, that is, ω=ω p -α2*t; The deceleration braking process is as follows: once the robot enters the deceleration process and the deceleration state is set to true, the robot will continue to decelerate until the minimum effective angular velocity ω2 is reduced and the remaining angle meets the stop judgment threshold, and the rotation action is completed.

5. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1, wherein: In step S1, the walking control refers to the speed control used for the robot in a moving state during path tracking, handling operations, etc., and the control includes: the acceleration stage, that is, gradually increasing the linear speed from the starting state to enable the robot to smoothly enter the path tracking state; the uniform speed stage, in the middle section of the path or on a straight path, the linear speed is stable in position to achieve efficient walking behavior; the deceleration stage, that is, when approaching the target position or when it is necessary to stop the operation, the linear speed is gradually reduced to ensure that the vehicle body stops smoothly, improve positioning accuracy and ensure the safety of the goods.

6. A method for controlling a mobile robot motion with dynamic acceleration and deceleration constraints according to claim 1 or 5, characterized in that: The acceleration and deceleration parameter settings of the walking control include the settings of the following speed control parameters: (1) Set the maximum linear velocity V1, in m / s, to limit the maximum speed of the robot during driving; (2) Set the linear acceleration to A1, unit: m / s 2 , used to control the acceleration process of the robot from a stationary state to the maximum travel speed, ensuring that the acceleration process is smooth and controlled; (3) Set the linear deceleration to A2, unit: m / s 2 , used to control the robot to slow down and stop when approaching the target point, to avoid exceeding the target position due to insufficient braking distance; (4) Set the minimum linear velocity to V2, in m / s, to prevent the driver from not responding or the vehicle from not moving due to the linear velocity being too low during low-speed driving, and to ensure effective movement during fine control. (5) Set the low-speed switching distance threshold to D1, in meters, to determine whether the distance between the robot and the target point enters the low-speed driving area. When the remaining distance is less than D1, the mobile robot will maintain the minimum linear speed V2. (6) Set the stopping distance to D2, in meters, to determine whether the vehicle has reached the task point; (7) Set the minimum turning speed to V3, in m / s, to keep the vehicle in a controllable state when the robot is in the turning or low-speed movement stage, and avoid dead zones or slipping in place.

7. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1 or 5, characterized in that: In step S2, the construction of the acceleration and deceleration gradient curve model includes a walking acceleration and deceleration gradient curve model that describes the dynamic characteristics of the linear velocity of the robot during walking. The walking acceleration and deceleration gradient curve model includes: When entering the control process for the first time or when the external setting resets the angular velocity, initialize the linear velocity V at the previous moment P = 0, and reset the deceleration state to false; if the robot meets the conditions for reaching the target point, the walking task is completed; The acceleration phase of the mobile robot is: Using the accelerated V above, calculate the distance you need to decelerate while walking in real time When the distance between the robot and the target point |ΔL|<L brake When the vehicle enters the deceleration braking process, that is: V=V p -A2*t; When the robot is in the acceleration phase or the constant speed phase, if there is a curve with a large curvature on the path, if the robot continues to maintain a high linear speed, the path tracking accuracy will decrease; To this end, the output linear velocity of the robot is constrained based on the real-time curvature value of the path. Assuming that the calculated curvature velocity is V cur , the final output control speed is: V=min(V cur (V); The curvature velocity calculation method includes: The path to be tracked is segmented offline according to the preset map resolution m to obtain a sequence of path points; Get the index of the nearest path point corresponding to the current posture of the robot. Starting from this index point, search for (K1*V1) / m path points in the front of the path and (K2*V1) / m path points in the back of the path, where K1 and K2 are preset constants and m is the map resolution. The forward path point set and the backward path point set together constitute the path sampling set. Calculate the slope angle between adjacent path points in the path sampling set. The calculation formula of the slope angle θ is: Among them, (x2, y2) and (x1, y1) are the coordinates of two adjacent path points; Accumulate the slope angles of all adjacent points in the path sampling set and add the accumulated values Set to no more than π; Add the accumulated value Bring in the high-speed function for calculating the curvature coefficient to get the curvature coefficient. The smaller the value, the flatter the path. When the value is zero, it means that the straight line path set is being tracked at this moment. Define the input but like , further adjusted to: Then the curvature velocity at the current moment is:

8. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 6, characterized in that: The judgment of whether the vehicle has reached the task point is to solve the problem that the mobile robot cannot accurately stop at the target point due to inertial slip or navigation error, and no longer directly use the robot's terminal target posture M (x m ,y m ,θ m ) as the parking decision point, but introduces a parking control extension point N(x n ,y n ,θ n ), which is obtained by extending the target posture along its direction by a distance D2. The calculation method of the reference control point N is: Among them: D2>0 means early parking, the robot will stop before the target point; D2=0 means strictly parking at the target point; D2<0 means the robot will stop after passing the target; A task reference line segment is constructed between the target point M and the extension point N, and a normal judgment line perpendicular to the direction of the line segment is constructed at point N as the boundary for whether the task point has been reached: when the robot's real-time position and the position L meters in front of the target point are on one side of the normal judgment line, it means that the robot has not reached the target point and needs to continue walking; when they are on both sides of the normal judgment line, it means that the robot has reached the target point and the walking task is completed, and the said L>|D2|.

9. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1, wherein: In step S3, the external control signal or environmental feedback signal includes one or more of the following situations: When the vehicle encounters an obstacle in front of it during its travel, it needs to reduce its travel speed. The travel acceleration and deceleration module will automatically reduce the maximum linear speed parameter. When the external system issues a pause command, the deceleration parameter will be increased and the target point position will be advanced, so that the speed of the mobile robot will be reduced to zero faster; When an obstacle is encountered abnormally or the vehicle is in a paused state, the maximum linear speed is restored to the value in the preset configuration parameters. The external control signal immediately reduces the angular velocity and / or linear velocity of the vehicle to zero in the event of an emergency, such as when the emergency stop button is pressed, the anti-collision bar is triggered, or the obstacle avoidance radar detects a close obstacle; After the above danger is eliminated, the vehicle body gradually accelerates from zero to the maximum speed at a preset acceleration.

10. The method for controlling the motion of a mobile robot with dynamic acceleration and deceleration constraints according to claim 1, wherein: In step S4, the path tracking module includes tracking control and nonlinear control.

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