Robot Axis Braking Control for Lower Emergency Stop Loads
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Solution Overview
Problem
Robot axis arrangements face high dynamic loads and varying braking effects due to manufacturing and assembly tolerances, leading to inefficient braking and potential structural damage during emergency stops.
Innovation Solution
A method and system for controlling the driving and braking forces of robot axes, using a control means to apply braking force based on dynamic variables, such as torque and speed, to manage loads and reduce structural stress by adjusting the braking and driving forces in opposite or same directions, and controlling the braking force to limit loads within predefined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the additional brake is quickly closed to bring the axis to a quick standstill during emergency stop, then the stopping time is reduced, but the robot structure and brake are subjected to high dynamic loads
Solution Approach 1:
The drive torque is reduced or reversed before the brake is fully engaged, preparing the system to absorb the braking load more gently. This preliminary action prevents the sudden application of full braking force that would otherwise create high dynamic loads on the robot structure and brake components.
Solution Approach 2:
The control means acts as a cushioning element by dynamically adjusting the drive torque to compensate for the braking force. This beforehand cushioning prevents the harsh impact that would occur if the brake were applied directly without gradual load management, thereby protecting the robot structure and brake from excessive dynamic loads.
2Device complexity
If the brake is designed only to fix the stationary axis, then the brake structure is simplified, but the brake cannot effectively manage high dynamic loads during emergency stopping
Solution Approach 1:
The drive system is given the additional function of assisting in the braking process. By enabling the drive to reduce or reverse torque during emergency stops, the system achieves multi-functionality where the drive both moves the robot during normal operation and actively participates in controlled stopping, thereby enhancing brake reliability without requiring a more complex brake structure.
Solution Approach 2:
The control means acts as an intermediary between the drive and the brake, coordinating their actions during emergency stops. This intermediary function allows the simple brake structure to work in conjunction with the drive system, distributing the braking load and ensuring reliable stopping performance without increasing brake complexity.
3Reliability
If manufacturing and assembly tolerances cause varying braking effects, then the brake application becomes unpredictable, but increasing brake force to compensate leads to even higher loads on the robot structure
Solution Approach 1:
The control means continuously monitors the braking process and dynamically adjusts the drive torque in response to actual braking conditions. This feedback mechanism compensates for variations caused by manufacturing and assembly tolerances, ensuring consistent and predictable braking effects without requiring excessive brake force that would increase loads on the robot structure.
Solution Approach 2:
The braking system transitions from a static, fixed-brake-force approach to a dynamic, adaptive control strategy. The control means continuously adjusts the drive torque during the braking process, allowing the system to respond to real-time conditions and tolerate variations in brake performance due to tolerances while maintaining safe and consistent stopping behavior.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the load on the robot structure and brake components by optimizing the braking process, ensuring safe and reliable stopping of robot axes, even under high-speed conditions, and extends the lifespan of the braking system.
Implementation Method 1
a brake for applying a braking force to the driven member
Implementation Method 2
a drive for applying a driving force to the output member
Data Source
Figure 1~2
Figure 3~4C
AI summary
A method according to the invention for braking a robot axis arrangement with at least one driven member (1) comprises the steps: applying a braking force to the driven member by a brake (5.1-5.4); and thereby controlling a driving force of a drive (4.1-4.4) acting on the driven member and/or the braking force on the basis of a dynamic variable of the driven member, which depends on the braking force.