Robotic Arm Tip-Following Control Without Homing Constraints
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Solution Overview
Problem
Existing robotic arm control methods, such as leader-follower algorithms, limit the motion capability of proximal segments and require predefined configurations for startup, making them ineffective for redundant mechanisms and inaccurate in path following, especially when dealing with complex environments.
Innovation Solution
A method that calculates a new arm shape using the current shape and desired tip position, allowing segments to move independently, ensuring accurate tip following by aligning segment orientations and positions with the path, even in dynamically changing environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a basic leader-follower algorithm is used to control the robotic arm, then the control implementation is simple, but the motion capability of proximal segments is lost and path following accuracy deteriorates
Solution Approach 1:
The robotic arm is divided into multiple independently controllable segments, where each segment can execute different motion commands rather than being constrained to copy the leader segment's motion. This segmentation enables proximal segments to contribute actively to path following while maintaining computational simplicity.
Solution Approach 2:
The control algorithm dynamically assigns different roles to different segments based on their position and capability. Proximal segments can perform lateral adjustments while distal segments focus on tip positioning, creating a dynamic division of labor that enhances overall adaptability without complicating the control structure.
2Device complexity
If a basic leader-follower algorithm is used to control the robotic arm, then the control structure is simple, but path following accuracy deteriorates
Solution Approach 1:
An intermediary computational layer is introduced that processes the desired tip trajectory and distributes appropriate motion commands to each segment. This intermediary algorithm coordinates segment motions to collectively achieve accurate path following while maintaining a relatively simple overall control structure.
Solution Approach 2:
The control approach merges the simplicity of leader-follower algorithms with the accuracy of coordinated motion control. By combining independent segment control with a unified path following objective, the system achieves high path following accuracy without the complexity of full inverse kinematics computation for each segment.
3Productivity
If the robotic arm uses a predefined path with data points, then the path following is structured, but the method is inaccurate for complex environments with multiple links per segment
Solution Approach 1:
The control system dynamically adjusts segment configurations based on real-time positioning needs rather than following a fixed predefined sequence. Each segment can independently adapt its position and orientation to accommodate complex environmental constraints while maintaining overall path following efficiency.
Solution Approach 2:
Different segments are allowed to exhibit different motion characteristics and control strategies based on their local requirements. Proximal segments may prioritize obstacle avoidance while distal segments focus on precise tip positioning, enabling accurate path following in complex environments without sacrificing overall efficiency.
4Measurement precision
If the robotic arm requires homing to a specific configuration, then the startup position is well-defined, but the ease of operation deteriorates due to configuration constraints
Solution Approach 1:
Instead of requiring the arm to move to a predefined configuration before operation, the system inverts the approach by accepting the current configuration as the starting point and computing the necessary motions from there. This eliminates the homing requirement while maintaining well-defined startup positions through computational coordination.
Solution Approach 2:
The control algorithm dynamically computes motion parameters based on the current arm configuration rather than requiring a fixed startup configuration. This parameter adaptation allows the system to operate from any position while maintaining precise control and well-defined operational states.
Data Source
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AI summary
The invention relates to a method of controlling the position of an elongate robotic arm comprising articulated segments. An actuator is associated with each segment to control its position, and a control system operates the actuators. Data representing the position of the arm is gathered and compared to input data that represents a required new position of a part of the arm. Data representing the required new position of the arm is then calculated, attempting to keep the remainder of the arm as close as possible to its previous position. The actuators are operated to move the arm into the new position. In tip following, the data representing the new position may define a path, and the arm may be fitted to the path by matching the position and orientation of a point on each pair of adjacent segments to that of the path.