Manipulator Variable Center-of-Gravity Unit for Deadweight Compensation
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Solution Overview
Problem
Conventional manipulators lack a deadweight compensation mechanism that accounts for the mass of objects held, leading to inefficiencies in energy consumption and motor size due to the absence of a mechanism to balance the weight of the object being manipulated.
Innovation Solution
A manipulator design incorporating a variable center-of-gravity unit with movable weights and a controller that adjusts the position of these weights to balance the manipulator's deadweight, allowing for reduced motor size and energy consumption by maintaining balance across multiple joints regardless of the object's presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional deadweight compensation mechanism is used (torque motor outside joint or weight balance), then the energy consumed by the torque motor is reduced and the manipulator size is reduced, but the mechanism does not account for the mass of objects held, leading to increased energy consumption when objects are manipulated
Solution Approach 1:
The patent implements a dynamic deadweight compensation mechanism where the counterweight position is adjustable along the arm. This allows the system to adapt to different object masses by changing the counterweight position, thereby maintaining energy efficiency across various operating conditions. The counterweight can be moved to different positions to balance the arm for different payload scenarios, resolving the contradiction between fixed compensation and adaptability.
Solution Approach 2:
The patent changes the parameter of counterweight position to achieve adaptive compensation. By varying the position of the counterweight along the arm, the system can compensate for different object masses. This parameter change allows the same mechanical structure to provide optimal deadweight compensation for both empty arm conditions and various loaded conditions, addressing the adaptability issue while maintaining energy efficiency.
2Adaptability or versatility
If a large torque motor is used to compensate for object mass, then the manipulator can handle objects of various masses, but the manipulator size increases and energy consumption increases
Solution Approach 1:
The patent uses a dynamic counterweight positioning system that can be adjusted to different positions along the arm. This allows a smaller motor to achieve compensation for various object masses by optimizing the counterweight position for each scenario, rather than requiring a large motor capable of handling the maximum possible mass in all conditions. The manipulator size is reduced while maintaining adaptability.
Solution Approach 2:
The patent employs a counterweight mechanism positioned along the arm to balance the arm's weight and compensate for object mass. By strategically positioning the counterweight, the system reduces the torque requirements for the motor, allowing for a smaller motor size while still achieving the ability to handle various object masses effectively.
3Adaptability or versatility
If a large torque motor is used to compensate for object mass, then the manipulator can handle objects of various masses, but the energy consumption increases
Solution Approach 1:
The patent implements a dynamic counterweight positioning system that optimizes the compensation for different object masses. By adjusting the counterweight position, the system minimizes the energy required for motor operation in each specific scenario, rather than continuously operating at the high energy level required for maximum load compensation. This resolves the contradiction between adaptability and energy consumption.
Solution Approach 2:
The patent changes the counterweight position parameter to achieve energy-efficient compensation for various object masses. By varying this parameter, the system can provide optimal deadweight compensation for each specific operating condition, reducing overall energy consumption while maintaining the ability to handle various object masses.
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 effectively reduces the force required to drive the joints, enabling a more compact and efficient manipulator by ensuring balance across various orientations and object states, thus minimizing the size and energy consumption of the actuators.
Implementation Method 1
A manipulator includes a base, a first joint, a first coupling member, a second joint, a second coupling member, a first arm, a second arm, a variable center-of-gravity unit, a holder, and a controller. The variable center-of-gravity unit including a first weight and a second weight. The controller controls the variable center-of-gravity unit to perform at least one of operations while the holder holds an object, the operations including a first operation for moving the first weight in a direction crossing the rotation axis of the first joint and a second operation for moving the second weight in a direction crossing the rotation axis of the second joint.
Implementation Method 2
The manipulator uses a deadweight compensation mechanism capable of cancelling the weight of the manipulator itself (i.e., the deadweight) with a mechanical structure. With this deadweight compensation mechanism, a power for maintaining the static state of the manipulator can be reduced.
Data Source
AI summary
According to an embodiment, a manipulator includes the following elements. The first joint has a rotation axis in a first direction crossing a gravity direction. The second joint has a rotation axis in a second direction crossing the first direction. The first arm and the second arm are coupled with the second joint along a third direction crossing the second direction. The variable center-of-gravity unit coupled with the first arm. The controller controls the variable center-of-gravity unit to perform an operation for moving the first weight of the variable center-of-gravity unit in a direction crossing the rotation axis of the first joint and/or an operation for moving the second weight of the variable center-of-gravity unit in a direction crossing the rotation axis of the second joint.