Targeting the user experience in the development of mobile machinery using real-time multibody simulation

Abstract

Applying a semi-recursive multibody approach enables the solution of the equations of motion of a complex system in real time. This makes it possible to conduct human-in-loop simulations and analyse the user experience. The idea of recognizing the user experience to produce more efficient, competitive, and user-friendly products has been limited thus far to the field of information technology and the development of light physical products. This study introduces a simulation modelling procedure for a complex forklift mast system that can be used to help analyse the user experience. A multibody forklift model is introduced that includes the electric motors, a pump, a freelift, a mainlift and tilt cylinders, actuators, pulley and chain mechanisms, contacts, and tyres. The viscoelastic behaviour of the chain during longitudinal and transverse movement is simulated using a discrete model approach. Triplex mast speeds and hydraulic system efficiencies across working cycles are used to verify the performance of the introduced real-time simulation model against measurements taken from an equivalent reference forklift. To better evaluate the developed model, experienced and inexperienced forklift drivers were asked to drive an updated simulator and provide feedback. User experience inputs that can be made available early on in development using this new modelling approach will permit experts to evaluate and design more efficient complex mechanical systems.

Estimating the Characteristic Curve of a Directional Control Valve in a Combined Multibody and Hydraulic System Using an Augmented Discrete Extended Kalman Filter

“…In the real world, the sensors shown in the Figure 1 can be replaced by sensor measurements obtained from a physical system, such as a forklift, a tractor, etc. [ 4 , 57 ]. To account for the system response, the sensor measurement vector includes the minimum number of measurements required by the ADEKF algorithm to estimate the states and parameters of a real system.…”

“…Multibody system dynamics (MBS) approaches enable the creation of the equations of motion that describe a mechanical system and relevant sub-components of complex mechanical systems [ 1 , 2 ]. The use of MBS leads to physics-based models that act as a single source of information [ 3 ] and represent the operation of an equivalent physical system in the real world [ 4 ]. The data generated by an MBS simulation model can be used to solve real-world problems throughout a product’s life cycle [ 5 ].…”

Physics-Based Digital Twins Merging With Machines: Cases of Mobile Log Crane and Rotating Machine

“…The equations of motion for a closed-loop system can be formulated by incorporating the cut-joint constrained equations into the dynamics of the open-loop system [26]. As demonstrated recently, the semirecursive formulation is well suited for real-time simulation applications [10], [27], [28]. The accuracy of MBS can be improved by also addressing the deformation of bodies, which results in a more computationally intensive simulation.…”

“…To demonstrate the feasibility of physics-based digital twins in the heavy equipment segment, the dynamics of a mobile log crane was modelled in independent coordinates using MBS formulations as a proof-of-concept system. MBS provides general formulations to build dynamic simulation models of industrial machines [10], [18], [28] which can be used in divergent phases of product lifecycle ranging from product development to maintenance. Using the MBS formulations in the presented case example makes it possible to reduce the number of sensors in the implementation of the digital twin.…”

Haptic Devices Based on Real-Time Dynamic Models of Multibody Systems

“…Running a multibody model in real-time requires sufficient computational power on the considered hardware. While it is possible to perform the online computation on a classic computer with Intel processor and Windows OS [ 19 ], it may not be the most robust solution. Besides, if one aims to perform an embedded simulation, the hardware is often limited.…”