Robot Arm Brake Hysteresis Control for Low-Heat Disengagement
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Solution Overview
Problem
Electro-magnetic brakes in robot arms for microsurgery require high power for neutralization and re-engagement, leading to heat generation and precision issues due to thermal expansion, which is economically disadvantageous and poses safety risks.
Innovation Solution
A joint arrangement for a robot arm with a brake device configured to operate at minimal power consumption using a hysteresis effect, where the brake device comprises a stator assembly and a rotor assembly with a permanent magnet and electromagnet arranged with a gap to maintain a stable disengagement state with reduced power usage, and a method employing Pulse Width Modulation (PWM) to manage power thresholds for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the electro-magnetic brake is operated with high power to neutralize the braking effect, then the brake can be disengaged, but power consumption increases and heat is generated
Solution Approach 1:
The brake device operates in periodic cycles, alternating between engagement and disengagement states. During disengagement, power is applied periodically rather than continuously, reducing overall power consumption while maintaining the ability to neutralize the braking effect when needed.
Solution Approach 2:
The system changes the power parameter dynamically based on the operational state. By adjusting the power level from high (during engagement neutralization) to minimal (during sustained disengagement), the system reduces energy consumption while maintaining brake functionality.
2Ease of operation
If the electro-magnetic brake is operated with high power for neutralization, then the brake can be disengaged, but heat generation increases causing thermal expansion
Solution Approach 1:
Power is supplied in periodic pulses rather than continuously during disengagement. This periodic action allows heat to dissipate between pulses, preventing excessive temperature buildup and thermal expansion while still maintaining brake disengagement.
Solution Approach 2:
The system converts the potential harm of heat generation into a benefit by using minimal power operation. The reduced power consumption naturally leads to reduced heat generation, and the periodic operation allows thermal management without additional cooling mechanisms.
3Ease of operation
If the brake device is kept disengaged with continuous power, then the brake remains released, but power consumption remains high
Solution Approach 1:
The brake device utilizes its own hysteresis characteristics to maintain the disengagement state. Once disengaged, the brake remains in this state due to its inherent magnetic hysteresis properties, requiring minimal power to maintain rather than continuous high power.
Solution Approach 2:
The power parameter is changed from a high sustained level to a minimal maintenance level once disengagement is achieved. This parameter change exploits the hysteresis effect to maintain the disengaged state with significantly reduced power consumption.
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
The solution reduces power consumption and heat generation, enhancing the economic and precision performance of the robot arm while improving safety by maintaining a stable disengagement state with lower power usage and minimizing thermal expansions.
Implementation Method 1
a magnetic field provided by a permanent magnet
Implementation Method 2
the magnetic field provided by said permanent magnet is usually displaced by an opposing electro-magnetic field
Implementation Method 3
the hysteresis effect of the brake device may occur in a range between a power required for disengagement and a power required for engagement
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention provides a joint arrangement (10) for a robot arm (20), especially a robot arm (20) for use in microsurgery, comprising: at least one brake device (100) being configured for engagement and for disengagement and comprising a stator assembly (102) and a rotor assembly (104), wherein the brake device (100) is further configured to be operable at a minimal power consumption in a disengagement state. The present invention further provides a method for operating a brake device (100) in a joint arrangement (10) for a robot arm (20), especially a robot arm (20) for use in microsurgery, the method at least comprising the following step: the brake device (100) is provided and configured for engagement and for disengagement, the brake device (100) comprising a stator assembly (102) and a rotor assembly (104), wherein the brake device (100) is further operated at a minimal power consumption in a disengagement state.