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Mobile Robots
Published in Bogdan M. Wilamowski, J. David Irwin, Control and Mechatronics, 2018
Miguel A. Salichs, Ramón Barber, María Malfaz
Differential steering configuration. The driving signals are the linear speed of the two driving wheels: v1, v2 (Figure 39.3). The kinematic equations of a point placed in the middle of the driving wheels are () x˙C=−v1+v22sin(θ)y˙C=v1+v22cos(θ)θ˙=v1−v2D
Sustainable Heavy Construction Equipment
Published in J.K. Yates, Daniel Castro-Lacouture, Sustainability in Engineering Design and Construction, 2018
J.K. Yates, Daniel Castro-Lacouture
In 2008, Caterpillar released a D7E electric bulldozer. According to the Engineering News Record (2008, p. 1), A 9L ACERT diesel drives a generator, whose wiring harness has effectively replaced the driveshaft. It runs a power inverter wired to two WC liquid-cooled electric motors mated to an axle containing two double-reduction gear sets. A third plenary set in between, powered hydraulically, controls differential steering. Transmission is continuously variable, eliminating the need for extra valving and gearing. The engines are beltless, and the entire machine weighs about 3,000 lb [1,360.77 kg] less than the current D7R. By taking out 60% of the moving parts and lightening the load, Cat is able to cut down on parasitic energy losses to get a 20% fuel economy improvement.
Optimal design of hybrid track-type dozers with two-planetary gear sets and clutches
Published in Johannes Edelmann, Manfred Plöchl, Peter E. Pfeffer, Advanced Vehicle Control AVEC’16, 2017
Z. Qin, Y. Luo, K. Li, Z. Pan, H. Peng
The research of the drive system for the track-type dozer (TTD) which is widely used for construction or agriculture is important. For crawler dozer which is used for construction, traditional transmissions using directly internal combustion engine (ICE) are always adopted, with high towing power, which costs lots of fuel consumption and has low energy efficiency. Hybrid power is an effective way to save the energy and reduce the emission. Hybrid electric crawler dozer has been researched for long time, while Caterpillar firstly made out the hybrid track-type dozer called D7E that has been proved with good performance using the electric generator, power inverter and propulsion module in the electric drive system to replace the traditional mechanical components. The system adopts a series hybrid powertrain. The engine and the generator work together to give the power to the two motors connected to the differential steering system to drive the dozer. D7E works without the traditional mechanical gearbox and can reduce the fuel economy by 20% compared with D7 which has same size while driven by traditional ICE transmission (Kwak, S. et al. 2010).
Multiobjective performance optimisation of a new differential steering concept
Published in Vehicle System Dynamics, 2022
Differential steering is a vehicle steering principle utilising traction force differences between left and right wheels of a steered axle which generates a steering moment about the kingpins to turn wheels in a desired direction. To date, this concept is used only for steering assist, named differential drive assisted steering system (DDAS) [1]. In the past decade, differential steering has been becoming an emerging steering solution as it may provide redundancy in steer-by-wire systems [2]. However, alternatively the differential steering concept may totally substitute any dedicated steering device to save costs or realise all-wheel steering in an all-wheel-drive vehicle layout with in-wheel motors [3].