Excavator Tilt-Rotator Control Remapping for Intuitive Tool Positioning
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Solution Overview
Problem
Operating an excavator with a tilt-rotator arrangement requires skilled coordination of multiple joint movements to precisely position and orient the tool, making it difficult for operators to seamlessly transition between manual and automated control, especially for complex and repetitive tasks.
Innovation Solution
A system that includes an input interface for user commands, a sensor data interface for real-time orientation determination, and a remapping unit that coordinates joint movements based on inverse kinematics to allow direct adjustment of the tool's position and orientation relative to a reference surface, enabling intuitive interplay between manual and automatic control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard excavator controls map each joystick movement to individual cylinder or joint movements, then the operator can control each joint independently, but the operator must coordinate multiple joint movements to achieve desired tool position and orientation
Solution Approach 1:
The patent introduces an intermediary control system that sits between the operator's joystick inputs and the individual joint actuators. This intermediary layer performs automated coordination and kinematic calculations, translating simple tool-position commands into the complex sequence of joint movements required. The operator interacts with a virtual tool-centered coordinate system rather than directly controlling each joint, effectively mediating the complexity away from the operator.
Solution Approach 2:
The control system performs self-service by automatically calculating and executing the coordinated joint movements needed to achieve the desired tool position and orientation. The system's own control computer handles the complex kinematic transformations and timing synchronization without requiring external operator intervention for each coordination decision. The excavator essentially controls itself based on high-level operator intent.
2Adaptability or versatility
If a tilt-rotator arrangement is added to increase flexibility and precision, then the tool can be rotated and swiveled in multiple directions, but the number of joints and coordination requirements increase significantly
Solution Approach 1:
The patent implements a universal control interface that handles multiple functions through a single unified system. The same joystick and control computer that manage the basic excavator arm movements also control the tilt-rotator's multiple rotational degrees of freedom. The control system provides a consistent tool-centered coordinate system regardless of which specific joint or attachment is being manipulated, allowing the operator to achieve various tool orientations without learning separate control schemes for each function.
Solution Approach 2:
The control system segments the complex multi-joint system into independent virtual degrees of freedom aligned with the tool's coordinate axes. Instead of controlling each physical joint (boom, stick, tilt, rotor) separately, the system segments control into three independent rotational movements around the tool's x, y, and z axes. This segmentation simplifies the operator's task by allowing independent adjustment of each rotational degree of freedom without coordinating the underlying physical joints.
3Productivity
If automated control functionalities with inverse kinematics are implemented, then movement profiles for preset trajectories can be generated, but the operator skill level required to assess current situation and take over manual control increases
Solution Approach 1:
The patent implements continuous feedback between the automated control system and the operator through the same intuitive tool-centered interface. The system constantly monitors the actual tool position and orientation, compares it with the desired trajectory, and automatically adjusts joint movements to correct deviations. The operator receives visual feedback showing the relationship between joystick commands and actual tool movement, enabling seamless transition between automated and manual modes without requiring advanced diagnostic skills.
Data Source
AI summary
A system for controlling movement of multiple links of an excavator can move a tool at the end of an excavator arm. The system includes a sensor data interface configured to receive sensor data for determining relative orientations of the multiple links with respect to each other, and a surface setting unit configured to access design data defining a reference surface. The system has a remapping unit configured to remap a user command for moving two links with respect to each other about a corresponding joint to a rotatory tool degree of freedom. The system then coordinates output signals, such that as a function of the remapped user command the tool is rotated within the associated rotatory tool degree of freedom, without the need that an operator coordinates underlying joint movements.