Spring-Compensated Robotic Joints for Dynamic Payload Balancing
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Solution Overview
Problem
Conventional robotic manipulators face challenges in dynamically adjusting gravity compensating torque when payloads change, leading to increased actuator efforts and reduced safety and robustness due to the reliance on passive gravity-balancing mechanisms and highly geared electric motors, which increase apparent inertia.
Innovation Solution
The implementation of a robotic manipulator with a four-bar linkage mechanism, gravity compensating springs, a spring adjustment mechanism, and an inertial actuator, where the spring adjustment mechanism dynamically alters the position of spring attachment points using a spring adjustment actuator, and the inertial actuator applies adjustable force to manage payload manipulation, enabled by feedback control for real-time compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive gravity-balancing mechanisms are used, then gravity compensation is achieved, but the system cannot dynamically adjust when payloads change
Solution Approach 1:
The patent applies dynamics by making the gravity compensation system adjustable and adaptive. The spring mechanism is no longer fixed but can be dynamically reconfigured through the spring adjustment actuator, allowing the system to adapt to varying payload conditions while maintaining a relatively simple mechanical structure.
Solution Approach 2:
The patent changes the parameters of the spring mechanism by allowing adjustment of spring attachment points and spring selection. This enables the gravity compensation torque to be modified according to payload weight, transforming a static parameter system into a dynamic one without requiring complete redesign of the compensation mechanism.
2Force
If highly geared electric motors are used, then torque is increased, but apparent inertia increases reducing safety and robustness
Solution Approach 1:
The patent uses spring mechanisms as counterweights to offset the gravitational torque on the robotic manipulator. By providing passive gravity compensation, the system reduces the torque burden on the electric motors, allowing them to operate with less gearing and thus reducing apparent inertia while maintaining sufficient torque for payload manipulation.
3Ease of operation
If actuators provide all gravity compensation torque, then payload manipulation is possible, but actuator effort increases
Solution Approach 1:
The patent segments the gravity compensation function into two parts: passive spring mechanisms that handle the majority of gravitational torque, and active actuators that provide only the remaining torque needed for acceleration and payload manipulation. This division significantly reduces actuator effort and energy consumption while maintaining full payload manipulation capability.
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 configuration allows for efficient and safe manipulation of dynamically varying payloads by reducing actuator efforts and maintaining gravity balance, enhancing the robotic manipulator's safety and robustness by actively adjusting gravity compensating torque and inertial forces.
Implementation Method 1
a plurality of spring compensated joints that enable the robotic manipulator to manipulate the position and the orientation of its payload in a spatial environment. Each spring compensated joint of the robotic manipulator may generally include a four-bar linkage mechanism, at least one gravity compensating spring
Implementation Method 2
a spring adjustment mechanism coupled to one end of the at least one gravity compensating spring and configured to alter a position of at least one of the spring attachment points
Implementation Method 3
an inertial actuator coupled between links of the four-bar linkage mechanism to effectuate rotational movement of the four-bar linkage mechanism and to apply an adjustable amount of force to accelerate and manipulate a payload handled by the robotic actuator
Data Source
AI summary
A robotic manipulator comprises a plurality of spring compensated joints, each including a four-bar linkage mechanism, a gravity compensating spring, a spring adjustment mechanism, a spring adjustment actuator and an inertial actuator. The gravity compensating spring is coupled between two links of the four-bar linkage mechanism at two different spring attachment points to provide a lifting force opposing a gravitational load force. The spring adjustment mechanism is coupled to alter a position of one of the spring attachment points. The spring adjustment actuator is coupled to move the spring adjustment mechanism to alter the position of the spring attachment point and adjust the amount of lifting force provided by the spring. The inertial actuator is coupled between links of the four-bar linkage mechanism to effectuate rotational movement of the four-bar linkage mechanism and apply an adjustable amount of force to accelerate and manipulate a payload handled by the robotic manipulator.