Lift Vehicle Multiple Capacity Envelope Control
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Solution Overview
Problem
Existing lift vehicles do not effectively utilize their full capabilities when operating with reduced loads, as the safe operating envelope is limited by maximum load capacity, and current systems rely on expensive 'infinite' measuring sensors, which are not justifiable for reduced load operations.
Innovation Solution
A multiple capacity system with a multiple envelope control system that adjusts the working envelope based on selected load modes using less expensive digital switches and limit switches, allowing for different operational characteristics between low and high load modes, and restricting boom functions to prevent unsafe positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If maximum load capacity envelope is used for all operations, then safety is ensured, but vehicle capabilities are not fully utilized when operating with reduced loads
Solution Approach 1:
The safe operating envelope is segmented into multiple capacity-based envelopes (e.g., 500 lb mode, 1000 lb mode). The control system divides the operational space into distinct zones corresponding to different load capacities, allowing the vehicle to operate safely within the appropriate envelope for each mode while maximizing capability utilization.
Solution Approach 2:
The safe operating envelope is made dynamic by automatically adjusting it based on the selected capacity mode. The control system dynamically modifies the envelope boundaries in real-time according to the load configuration, enabling the vehicle to adapt its operational limits to match the actual load being carried.
2Measurement precision
If expensive 'infinite' measuring sensors are used to determine boom position, then precise envelope control is achieved, but manufacturing costs increase
Solution Approach 1:
The patent replaces expensive 'infinite' measuring sensors with more economical discrete position measuring switches (digital switches). These cheaper sensors are positioned at specific locations along the boom to define position zones, providing sufficient measurement precision for envelope control without the high cost of continuous 'infinite' sensors.
Solution Approach 2:
The patent extracts only the essential measurement points needed for envelope control rather than using continuous 'infinite' sensors. By placing discrete switches at critical positions (e.g., to define position zones), the system obtains sufficient measurement data with fewer, cheaper sensors, removing the unnecessary complexity and cost of infinite-length sensing.
3Ease of manufacture
If discrete position measuring switches are used instead of 'infinite' sensors, then manufacturing cost is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent applies local quality by placing discrete measuring switches at specific critical positions along the boom rather than using continuous sensing. The switches are positioned at locations that define the boundaries of position zones, providing locally precise measurement exactly where needed for envelope control while reducing overall system cost.
Solution Approach 2:
The patent substitutes mechanical 'infinite' sensors with an electrical/control-based discrete switching system. The digital switches provide sufficient measurement precision for control purposes through electrical signals rather than mechanical continuous measurement, achieving cost reduction without sacrificing functional precision.
4Adaptability or versatility
If multiple capacity modes are implemented, then vehicle versatility is improved, but control system complexity increases
Solution Approach 1:
The control system is designed with multi-functionality to handle multiple capacity modes (e.g., 500 lb mode, 1000 lb mode) within a single unified controller. The same control system automatically adapts to different capacity configurations, managing envelope definition, sensor interpretation, and boom function restrictions across all modes without requiring separate control systems for each capacity.
Data Source
AI summary
A multiple envelope control system and method expands the operating capabilities of a lift vehicle. The vehicle includes a platform mounted to a telescoping main boom. The main boom is configured for lift/lower function and telescope function. The multiple envelope control system includes a selector switch for selecting between a plurality of capacity modes including at least a low load mode and a high load mode. A plurality of sensors are strategically positioned on the main boom to cooperatively define position zones of the platform. A control system determines in which position zone the platform located according to signals from the plurality of sensors. The control system controls an envelope of the platform based on a position of the selector switch. By strategically positioning the sensors to define the position zones, inexpensive switches, such as limit switches or the like, can be used, thereby reducing manufacturing costs of the machine.