Mobile Body Obstacle Avoidance Control With Distance-Based Yaw Correction
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Solution Overview
Problem
Existing control devices for mobile bodies, such as those described in Japanese Patent Application Laid-Open No. H07-110711, face challenges in promptly correcting the forward velocity and yaw rate when the distance to an obstacle becomes close, leading to delayed evasive actions and increased risk of collision with virtual or real obstacles.
Innovation Solution
A control device that includes a basic movement command generation unit, a movement command correction unit, and a movement control unit, which corrects the movement command by increasing the yaw rate and restricting velocity as the distance to an obstacle decreases, ensuring the mobile body smoothly avoids obstacles by generating a yaw rate in the direction away from the obstacle and reducing velocity promptly when close.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the repulsive force and frictional force are set to be small when the distance is close to the predetermined value, then the mobile body can move smoothly, but the correction of forward velocity and yaw rate is insufficient, causing delayed evasive action
Solution Approach 1:
The patent applies dynamics by making the correction force dynamically adjustable based on the distance to the obstacle. When the distance is close to the predetermined value, a small correction force is applied to maintain smooth movement. When the distance becomes equal to or less than the predetermined value, the correction force is increased to ensure timely evasive action. This dynamic adjustment resolves the contradiction between smooth movement and timely response.
Solution Approach 2:
The patent changes the parameter of correction force magnitude based on the distance condition. By switching from a small correction force (when distance > predetermined value) to a large correction force (when distance ≤ predetermined value), the system achieves both smooth movement during normal operation and reliable evasive action when needed.
2Reliability
If the repulsive force or frictional force is set when the distance becomes the predetermined value or less, then obstacle avoidance is enabled, but the operator cannot sensitively recognize that the mobile body is too close to the obstacle
Solution Approach 1:
The patent implements feedback by providing visual display information to the operator when the distance to the obstacle becomes equal to or less than the predetermined value. This feedback mechanism allows the operator to sensitively recognize the close proximity to the obstacle while the system simultaneously applies the repulsive force for obstacle avoidance, resolving the contradiction between automated avoidance and operator awareness.
3Reliability
If the yaw rate is increased promptly when the distance becomes the predetermined value or less, then the evasive action is timely, but the movement may become abrupt and less smooth
Solution Approach 1:
The patent applies dynamics by implementing a two-stage correction force strategy. In the first stage (distance > predetermined value), a small correction force maintains smooth movement. In the second stage (distance ≤ predetermined value), a large correction force ensures timely evasive action. The transition between stages is managed dynamically based on the distance condition, achieving both smoothness and timeliness.
Data Source
AI summary
The control device (20) corrects a basic movement command for a mobile body (1), which is based on an operator's maneuvering operation, in accordance with a positional relationship between the mobile body and an obstacle, and performs movement control of the mobile body (1) in accordance with the corrected movement command. The control device (20) is configured to correct the basic movement command, when a distance d between the obstacle and the mobile body (1) has become a predetermined value d1 or less, to cause a yaw rate in a direction away from the obstacle to be additionally generated on the mobile body (1), and also configured to correct the basic movement command so as to cause a rate of increase in magnitude of the yaw rate with respect to a decrease of the distance to be increased as the distance d is closer to the predetermined value d1.