Robot Arm Synchronization Using a Master Axis Trajectory
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Solution Overview
Problem
Industrial robots face challenges in synchronizing their movement with external devices, particularly when executing pre-planned motion trajectories, as existing systems rely on online trajectory calculation and position feedback, which can lead to inefficiencies and loss of synchronization during dynamic movements.
Innovation Solution
The robot system utilizes an external master axis to generate control signals for optimized offline trajectory planning, ensuring synchronized movement by directly relating the master axis position to robot joint positions, velocities, and accelerations, using digital or analog signals within defined limits, and allows for dynamic adjustments to maintain synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If online trajectory calculation is used during robot program execution, then the robot can adapt to dynamic changes in real-time, but the synchronization with external master devices is lost and execution efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal trajectory offline before execution. The complete movement path with all position, velocity, and acceleration data is computed in advance and stored in memory. During online execution, the robot simply follows this pre-calculated trajectory by reading stored data points, eliminating the need for real-time recalculation and ensuring synchronization with external master devices while maintaining execution efficiency.
2Productivity
If the robot executes pre-planned optimized trajectories, then execution efficiency is improved, but the ability to handle dynamic speed changes from external devices is reduced
Solution Approach 1:
The patent applies dynamics by creating a hybrid control system that combines offline optimization with online adaptability. The pre-calculated trajectory provides the optimal path, but the system dynamically adjusts execution by interpolating between stored data points based on real-time master axis position feedback. This allows the robot to maintain optimal motion patterns while adapting to dynamic speed changes from external devices through real-time position-based triggering of pre-computed trajectory segments.
3Reliability
If position feedback from the robot is used for control, then closed-loop control is achieved, but the complexity of synchronizing with external master devices increases
Solution Approach 1:
The patent applies the intermediary principle by introducing a master axis position signal as a mediator between the external master device and the robot controller. Instead of directly comparing robot position with master device position, the system uses the master axis position signal to trigger and control the execution of pre-calculated trajectory segments. This intermediary approach simplifies synchronization by decoupling the two systems while maintaining coordination through the shared trajectory data structure.
Data Source
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AI summary
The invention is related to a robot system (30) for synchronizing the movement of a robot arm (32) to a master device (40,42,44), wherein the system comprises a master device (40,42,44), a robot arm (32) with a moveable tip (34) and at least two degrees of freedom in movement and a robot controller (36) which controls the movement of the tip (34) of the robot arm (32) along a predetermined movement path (38, 68, 86) between a start- (70) and an end- (72) position. The robot controller (36) comprises input means (50) for a control signal (52, 62) for values between a first (64) and a second (66) limit, wherein the control signal (52, 62)is generated from source means (48) of the master device (40,42,44) and describes consecutive positions of a movement axis (46,90) of the master device (40,42,44). The robot controller (36) assigns each value of the control signal (52, 62) to a related position of the tip (34) of the robot arm (32) along the predetermined movement path (38, 68, 86) and controls the movement of the tip (34) of the robot arm (32) along the predetermined movement path (38, 68, 86) dependent on the respective values of the control signal (52, 62). While synchronizing the movement of the robot arm with an external axis, a sensor or control device is permanently providing the actual position of the axis to be synchronized with the robot controller, which determines, whether there is a deviation from the desired synchronized state or not.