Forestry Machine Leveling Control System for Pitch and Roll Envelope
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Solution Overview
Problem
Forestry machines face difficulties in leveling operations on uneven terrain due to limited operating envelopes caused by hydraulic cylinder lengths and abrupt cut-off mechanisms, which restrict movement and increase operator complexity.
Innovation Solution
A leveling control system utilizing position sensors to measure and control pitch and roll angles, allowing for automatic leveling and expanded operating envelopes by translating operator commands relative to the cab frame of reference, thus preventing mechanical interference and enhancing operational flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shortened hydraulic cylinders are used to prevent mechanical contact between the undercarriage and turntable support, then mechanical interference is prevented, but the operating envelope of the leveling mechanism is limited
Solution Approach 1:
The patent replaces the mechanical limit imposed by shortened hydraulic cylinders with an electronic control system. The control system monitors cylinder extension and uses feedback to prevent mechanical contact between the undercarriage and turntable support, while allowing the cylinders to be longer for greater operating envelope. This substitutes mechanical constraints with electronic control boundaries.
Solution Approach 2:
The patent implements a feedback control system that monitors the position and orientation of the turntable support relative to the undercarriage. The control system receives feedback from sensors and adjusts hydraulic cylinder extension accordingly, enabling the use of longer cylinders while preventing mechanical contact through active control rather than passive mechanical limits.
2Reliability
If limit switches are used to prevent damaging contact, then mechanical interference is prevented, but the operating envelope is smaller than the actual interference-free envelope
Solution Approach 1:
The patent replaces mechanical limit switches with an electronic control system that calculates and enforces operational boundaries. The control system uses sensor feedback to determine the precise limits of safe operation and controls hydraulic cylinder extension accordingly, eliminating the need for conservative mechanical limit switches that reduce the operating envelope.
Solution Approach 2:
The patent transitions from static mechanical limits (fixed limit switches) to dynamic electronic control boundaries. The control system continuously adjusts operational limits based on real-time sensor feedback about the relative positions of the undercarriage and turntable support, enabling the full interference-free operating envelope to be utilized safely.
3Adaptability or versatility
If the cab is rotated 360° relative to the undercarriage, then operational flexibility is increased, but operator control complexity increases
Solution Approach 1:
The patent replaces the mechanical coupling between cab orientation and control direction with an electronic control system. The control system receives cab orientation data from sensors and automatically transforms operator commands from the cab's reference frame to the undercarriage's reference frame, eliminating the complexity of manual coordination while maintaining full operational flexibility.
Solution Approach 2:
The control system acts as an intermediary between the operator's commands in the cab reference frame and the actual leveling mechanism control in the undercarriage reference frame. It automatically handles the coordinate transformation based on cab orientation, allowing the operator to control the machine intuitively without needing to understand the complex spatial relationships.
Data Source
AI summary
The present invention provides a leveling control system for a forestry machine (10) employing position sensors that relay information about the orientation of the carriage (12) in relation to the swing-house assembly (14) in order to control roll and pitch in a manner that maximizes the operating envelop of the leveling mechanism (38). The angles of pitch and roll of the swing-house assembly (14) in relation to the carriage (12) are measured and/or calculated and a controller (24) limits operation of the leveling mechanism (38) to an operating envelop that may be described in terms of pitch and droll. The cylinders (54, 56) are decelerated gradually as the operating envelop is approached. The controller (24) can include an automatic leveling mode. The controller (24) can change the function of the fore, aft, left and right operator controls so that they are true from the operator's frame of reference regardless of the rotary position of the cab relative to the carriage (12).