Electrification of existing product lines while undergoing digital transformation is a challenge facing OEMs on their ‘zero-emission journeys’ today. What is the overlap between these separate challenges? Many have engineered, produced, and maintained multiple generations of internal combustion (IC) products, but few have deep or broad experience with electric variants. Whether for heavy “off-highway”, consumer light vehicular, or airborne mobility, digital transformation and electrification affect how we conduct business today while setting a course toward the future. Current designs blend a century of practical experience with insights gained in recent years using digital analysis. Design requirements and engineering criteria reflect our cumulative knowledge, but because we are still in our first or second generation of electric product variants, the right way to engineer, produce, operate, and maintain our electric product lines might still reside in the “undiscovered country”, the future.
What most “know” about design-for-manufacturing-assembly and design-for-service is knowledge collected over several decades; engineering, assembling, operating, and maintaining internal combustion products. Some design requirements originate from digital engineering, while many others may have arrived after years of hardship, design iterations, process alternatives, and trial-and-error during production as worker populations struggle to make do with the way things were designed then trying to make them better.
There are no Pareto charts available with past years of production data yet. We lack distributed experience in maintaining products that may not arrive on the market for several years. When we envision our electric future, we cannot plan to simply exchange internal combustion powertrains for batteries and electric motors. Institutional technical memory lags in planning, engineering, and implementation of human-centric processes for these new products—procedures where people are required to interact with the proposed products during activities like assembly, maintenance, or operative use. In this post, we will consider how electrification impacts our digital engineering methodologies and how we prepare for human interaction with novel products.
Powertrain radiation, muffler noise, rattle and the acoustic behavior of seals, grommets and instrumentation panels can affect both the overall acoustic performance of construction equipment and the end user’s perception. Being equipped with vibro-acoustic simulation software, Virtual Prototypes help understand noise contributors faster than physical tests, enabling you to assess alternative designs, to reduce design iterations to meet regulations, or to propose efficient countermeasures – even if the product is already in the field.
When looking at exterior noise for construction equipment, Virtual Prototyping enables the prediction of sound power levels according to regulations including ISO 6395. Using different modeling techniques such as Boundary Element, Ray Tracing or Statistical Energy Analysis (SEA), different noise control treatments can be virtually tested in order to reach the desired acoustic performance, while saving time and cutting additional costs.
In addition, interior noise is tightly connected to operator safety and comfort and it’s an important brand differentiator for heavy machinery OEMsInterior noise can be addressed by statistical simulation methods like SEA to efficiently achieve high frequency comfort goals, or by deterministic methods such as Finite Elements to take into account the precise shape of the interior and the detailed composition of the sound package. With the advent of hands-free devices and the need for the operator to communicate with the construction cab, speech clarity analyses become crucial to ensure that infotainment systems are designed correctly.
Finally, tool noise can be an important contributor to both interior and exterior noise performance. Being able to predict the noise that will be emitted during heavy machinery operations is instrumental to reach acoustic targets. Most of the time, engineers will use component level simulation using the Boundary Element method, that can then be leveraged in system simulation.
A second important aspect of operator comfort are the vibrations that the driver feels in the cabin while operating the equipment. Using a physics-based model of the machine to consider vehicle dynamics, it‘s possible to calculate the propagation of forces, the torques and the pressures and other physical quantities that are occurring in the machine from their source through the vehicle frame to the seat rail, and in so doing, generate performance indicators to predict how comfortable the operator would be during typical operation cycles.
From early design stages, placing a Virtual Prototype of a machine into a Virtual Proving Ground, enables engineers to test out different design concepts and evaluate their effect on operator comfort. Going further through the development and test cycle, our customers use these same models for additional analyses such as stability or tipping safety as well as energy efficiency.
Wheel loaders are subject to various vibration and shock excitations during their work cycles. The integration of suspension systems ensures high levels of operator comfort and safety. Engineers at Liebherr Bischofshofen in Austria have been using the system modeling software SimulationX for several years to improve the dynamics of their machines, avoiding disturbances such as the “jumping man” effect. By using system simulation they analyze and optimize the vibrational behavior of wheel loaders with virtual prototypes in an efficient virtual development environment, which helps reduce physical test efforts.
As heavy equipment becomes fitted with more and more sensors, the possibilities for developing advanced safety functionalities are also increasing. The image below shows a Virtual Test Platform for an emergency braking function: here too, we are using a system model to represent the machine dynamics of the mechanical and hydraulic systems. Mounted on the machine are virtual sensors, in particular a radar sensor that will simulate the distance and angle between the machine and a vehicle. In addition to the virtual machine and sensors, there is an emergency braking algorithm, reading in the sensor data and sending an emergency brake signal to the machine model.
All these examples show how Virtual Prototyping brings together the various engineering tasks and groups to collaborate collectively on one virtual test platform for developing advanced functionalities for ultimate comfort and safety.
The power systems of industrial heavy machinery and off-highway vehicles can determine the potential layout of a product itself where electric updates could widely influence its architecture or topology. We see that in automotive EVs with the emergence of Frunks—front trunks or cargo spaces occupying the compartments previously dedicated to IC engines—or how batteries play larger roles within the safety structure of cars. However, while the configuration of passenger cars is more about aesthetics or style, off-highway heavy industrial machines can be more functional in their layout.
Conventionally, a large single ICE is connected to a transmission that converts engine rpm into rolling motion at the wheels, spins pumps for hydraulic and pneumatic systems and kinetic generators to power electrical systems; but when we electrify heavy machines will the same layout be necessary or even desirable. In a webinar about electrification challenges, one of my colleagues from our system simulation team postulated if electric loader design could benefit from distributed hydraulic power sources rather than a single centralized supply with hoses transferring the pressurized fluid throughout the design. After all, once we remove the ICE as the source of work, we can broaden design flexibility.
Using ESI’s System Simulation solution SimulationX, they found arguments for and against engineering a decentralized hydraulic system coming down to cost vs. energy efficiency, analogous to the range for EV automotive engineering.
Shifting to a decentralized hydraulic system creates new challenges/opportunities when it comes to the layout of the product, its manufacturing requirements, and service maintenance procedures. If this new generation of Electric Powertrain loaders was to be produced, could we produce, operate, or maintain it the way we do now? New risks emerge for heavy machinery manufacturers traversing digital transformation, the lack of physical product availability and pre-production environments makes commissioning the next assembly line or cells difficult.
We don’t have a century of experience producing electric product variants; therefore we need to consider that new products, assembly processes, and service requirements might yet exhibit sub-optimal design for safe operation, efficient maintenance, and sustainable production once people gain experience with new product variants in assembly or service processes. To accelerate discovery of and to mitigate risks, our customers perform reviews in the Virtual Reality (VR) where teams experience future products within the processes where humans interact with them—what we dubbed Human-Centric Product & Process Validation.
Human-Centric Process reviews allow users to integrate new product CAD data in an immersive virtual environment with proposed tooling, production assist devices, and assembly line hardware. While in VR, the user can visualize design variants to evaluate assumptions regarding the packaging and space claim within their design envelope. Will technicians be able to see what they need to assemble or service the proposed electric product? They can analyze the clearance required and propose new installation paths or packaging requirements. They can synthesize the performance of assembly tasks in a virtual version of the future plant and evaluate assembly order to validate production processes; they can conduct trials to remove or replace components to validate proposed service methods.
When we consider the ways that process plans and tooling for new products affect human workers; we recognize value toward enterprise outcomes (illustrated above):
Each decision regarding the Systems Design for new machines—alternative layout of systems, variant topology, addition, or elimination of componentry—potentially affects the ability of people to effectively operate, assemble, and service. A conclusive answer to the initial thesis from the systems team presented in this post, “should we decentralize the hydraulics system or rely on same topology as the ICE version”, requires not only the validation in Systems Engineering outputs but also a verification that the decision will not invalidate other aspects of process plans.
Continue reading about the different aspects of design validation of Human-Centric Product and Process design concerns that emerge from the consideration of electrification of a conventionally ICE product:
Don't miss our On-Demand Webinar on Human Centric Process Validation & Immersive Product Integration to see how to validate product integration and manufacturing & maintenance processes early in a human-centric way.