For all the remarkable advances in machine technology that have taken place over recent years, the most valuable component aboard any piece of mobile equipment is still the operator, which is why ergonomics is such an important factor in machine design.
When ergonomics are properly considered, the operator is more comfortable and, as a consequence, works more efficiently. Good design can not only maximize operator productivity but also enhance safety, a particularly important concern in the off-highway sector.
Designers of all kinds of machines from forklifts and cranes, to construction and agricultural vehicles, have taken great steps to improve their vehicles by introducing advances in machine control and ergonomics. In particular, strong advances have been made in the provision of integrated electronic controls for hydraulic systems. These developments have not only introduced levels of functionality that have previously been difficult to achieve but have also improved safety by separating operators from potentially dangerous machine systems.
The ergonomic design of parts that are constantly in use, such as keyboards and screens, can make a big difference to safety and efficiency, and the incorporation of multiple control functions in one simple interface has marked a significant advance in machine control.
Virtual terminals are now available for a wide variety of off-highway equipment. Parker Hannifin’s ISOBUS-VT terminal, for example, is available for use in a range of agricultural machinery and enables equipment selection, setup, and monitoring via a large 5.7-in color anti-glare TFT display in a lightweight and rugged enclosure with a sequence of front-mounted and backlit soft keys. The ISOBUS-VT can be used as the primary HMI for any ISO 11783 compatible system, enabling an operator to control vehicle and auxiliary equipment from a central unit via a suitable network interconnection unit, regardless of manufacturer.
Improved safety and ergonomics for machine operators have been major design objectives in the development of the interface between hydraulic motion and positioning circuits as well as the electronic systems that provide ever increasing levels of control, functionality, and diagnostics.
The latest systems, such as Parker’s IQAN technology, can even change the characteristics of machinery depending on who is in charge of operation, so that functionality is completely tailored to each user. In applications such as those within the construction industry where conditions can be harsh and safety is always a high priority, the ability to customize settings makes improper use extremely unlikely, thus reducing the risk of personal injury or equipment damage, while also minimizing the stress levels of operators.
To examine how technology such as IQAN is used to control off-highway vehicles, take a look at forklift trucks. The IQAN system includes control and display modules that can be used either in-cab or elsewhere on a machine to allow operators to manage different aspects of the hydraulic system, providing real-time data monitoring and diagnostics and interfacing with engine management or other machine systems for optimized control.
At the next level down, the functional hydraulic components include bi-directional, proportional or solenoid valves, directly operated via a sequence of control modules and connected in turn to the workhorses of every hydraulic system: the actuators.
Actuators are generally used for raising, lowering, or tilting masts and for operating a wide variety of attachments, ranging from forks to sideshifters, clamps, and positioners. This method of control is not only convenient but also enhances safety by separating the operator from the potentially hazardous machine control area. Computer technology has thus transformed hydraulics from what is sometimes perceived as a relatively inexact but powerful tool into a precise, almost infinitely variable method of motion and positional control.
As with many other off-highway vehicles in the construction, quarrying, and agricultural industries, forklifts can use single- or multi-axis joysticks to exercise precise machine control, and this capability has made a major contribution to enhancing safety and reducing stress and fatigue on off-highway operators.
These joysticks can provide very high levels of accuracy in motion control at the same time as minimizing the risk of RSI, while operators can set their control consoles to enable hydraulic "lock-out" and thus prevent unintentional movement of the joystick. The health and safety benefits of executing tasks automatically via a single control mechanism from within a vehicle cab, as opposed to operating exterior equipment while exposed to such harsh environments as construction sites and quarries, need little explanation.
As well as easing the physical burden, the latest software for hydraulic control can reduce the mental strain on off-highway operators by calculating the fastest, safest way to complete a task, removing the need to keep several different parameters in mind at one time.
Indeed, there are several features offered by today’s control modules that simplify operation. Flexible programmable visual interfaces are able to display selected information such as graphs that enable operators to efficiently execute tasks, and crucially, these interfaces can do so clearly and in plain language. If a fault does occur in equipment, it is immediately displayed on the master module, reducing both operator stress and the need to allot time and resources to manual diagnostics.
Machine guidance and control software can also now incorporate advanced positioning and tracking systems that, for instance, allow construction vehicle operators to calculate how much material needs to be removed when grading a construction site and the most efficient method to remove and transport that material to another location.
Using a combination of GPS, laser-guidance signals, and onboard sensors, a bulldozer can automatically scrape a precisely controlled level of material from the work surface, leaving the operator to carry out the relatively simple task of guiding the vehicle in the right direction.
As with operator controls, cab design significantly affects the ability of the operator to conduct duties efficiently and safely. Designers can now take advantage of advances in various technologies to improve conditions within the cab since the by-products of many such advances can assist in the ergonomic design of cabs.
For example, integrated electronic controls such as the virtual terminal mentioned above allow noisier components to be mounted at a distance from the operator, or concealed inside acoustic enclosures, while noise is also being reduced by high-performance hydraulic pumps that reduce effects such as flow ripple.
Integrated electrohydraulic actuators can be installed at a safe distance from operators with all components integrated into a robust monobloc housing, offering a tough alternative to traditional hydraulic or electro-mechanical methods in applications where motion systems need to offer high levels of power density, such as moving and locking lifts and hoists.
Enhanced ergonomics and user-friendly machine control systems have greatly improved productivity in off-highway applications because operators interface with machines in an entirely natural way with minimum stress.
Multifunctional joysticks fitted to operator seat armrests require minimal movement to send numerous operator signals to huge powerful machines, greatly improving the performance, safety, and usability of mobile hydraulic equipment.
The ability to tailor systems to meet the specific needs of each user offers greater efficiency and reduced operating costs, which inevitably will drive ever-more powerful innovations in the design and production of mobile and off-highway equipment.
Peter Söderberg, Group Promotion Manager at Parker Hannifin Hydraulics Group Europe, wrote this article for SAE Off-Highway Engineering.