Industrial Robot Trajectory Control for External Attachment Loads
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Solution Overview
Problem
Existing robotic manipulators face challenges in designing attachments due to inaccurate estimation of forces and torques, leading to potential failure or unnecessary weight and reduced performance, with current solutions often restricting speed and acceleration in an iterative and non-optimal manner.
Innovation Solution
A method for calculating load values at locations outside the kinematic chain of a robotic manipulator, using a control system to provide candidate trajectories, receive load location inputs, and adjust trajectories based on load constraints to optimize design and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If attachments are dimensioned based on mechanical engineer estimation of forces and torques, then design process is simple, but attachment strength is insufficient or overdesigned leading to increased weight
Solution Approach 1:
The patent replaces manual mechanical estimation with automated computer-based dynamic simulation. The system uses software to calculate actual forces and torques on the attachment during manipulator operation, substituting the mechanical engineer's subjective estimation with objective computational analysis. This resolves the contradiction by providing accurate strength data without complicating the design process.
Solution Approach 2:
The patent performs load calculations and dynamic simulations during the design phase before the attachment is manufactured. By calculating the actual forces and torques in advance using computer simulation, the design process identifies optimal attachment dimensions prior to manufacturing, preventing both underdesign and overdesign while maintaining design simplicity.
2Reliability
If speed and acceleration are restricted globally to reduce loads on sensitive attachment, then attachment failure is prevented, but manipulator performance is unnecessarily reduced
Solution Approach 1:
The patent applies local quality by restricting speed and acceleration only in specific regions of the workspace where the attachment is susceptible to high loads, rather than globally limiting performance. The system identifies critical zones through dynamic simulation and applies constraints locally, allowing the manipulator to operate at full performance in safe regions while protecting the attachment in vulnerable regions.
Solution Approach 2:
The patent uses dynamic constraint adjustment based on real-time manipulator state and attachment conditions. Rather than static global limits, the system dynamically modifies speed and acceleration constraints based on current load conditions, manipulator configuration, and attachment sensitivity, optimizing both reliability and performance through adaptive control.
3Force
If acceleration is limited based on particular attachment, then loads are reduced, but attachment can still experience high loads with low accelerations risking failure
Solution Approach 1:
The patent changes from single-parameter acceleration limiting to multi-parameter control including speed, acceleration, and trajectory shaping. The system adjusts multiple motion parameters simultaneously based on attachment characteristics and workspace location, preventing high loads that result from any single parameter combination rather than relying on acceleration limits alone.
Solution Approach 2:
The patent implements feedback through dynamic simulation and load monitoring to continuously assess attachment loads during manipulator operation. The system uses this feedback to adjust trajectory planning and motion parameters in real-time, ensuring loads remain within safe limits while maximizing manipulator performance, rather than using fixed acceleration limits.
4Strength
If attachment is made heavier to account for underestimated loads, then structural integrity is improved, but manipulator acceleration must be reduced and lifetime of actuators is reduced
Solution Approach 1:
The patent performs comprehensive dynamic load analysis during the design phase to accurately determine the required attachment weight and strength. By calculating actual forces and torques before manufacturing, the system optimizes attachment mass to be sufficient for structural integrity without excessive weight, preventing actuator overload and extending component lifetime from the outset.
Data Source
AI summary
A method of handling a manipulator of an industrial robot, the manipulator including a base member, a mounting interface and a kinematic chain between the base member and the mounting interface, the kinematic chain including the base member, the mounting interface and at least one controllable joint, the method including providing a candidate trajectory for the manipulator, the candidate trajectory being associated with a candidate path; receiving a load location input from a user, the load location input being associated with a load location associated with the industrial robot outside the kinematic chain; and calculating load values of a load parameter that will affect the load location if the candidate trajectory is executed. A control system and an industrial robot are also provided.