The design of a vehicle frame is largely dependent on the loads applied on the suspension and heavy parts mounting points. These loads can either be estimated through full analytical multibody dynamic simulations, or from semi-analytical simulations in which tire and road sub-models are not included and external vehicle loads, recorded during field testing, are used as inputs to the wheel hubs. Several semi-analytical methods exist, with various modeling architectures, yet, it is unclear how one method over another improves frame loads prediction accuracy. This study shows that a semi-analytical method that constrains the vehicle frame center of gravity movement along a recorded trajectory, using a control algorithm, leads to an accuracy within 1% for predicting frame loads, when compared to reference loads from a full analytical model. The control algorithm computes six degrees of freedom forces and moments applied at the vehicle center of gravity to closely follow the recorded vehicle trajectory. It is also shown that modeling the flexibility of the suspension arms and controlling wheel hub angular velocity both contribute in improving frame loads accuracy, while an acquisition frequency of 200 Hz appears to be sufficient to capture load dynamics for several maneuvers. Knowledge of these loads helps engineers perform appropriate dimensioning of vehicle structural components therefore ensuring their reliability under various driving conditions.

We present in this paper two new products for high-temperature, low-voltage (2.8V to 5.5V) power management applications. The first product is an original implementation of a monolithic low dropout regulator (XTR70010), able to deliver up to 1A at 230°C with less than 1V of dropout. This new voltage regulator can source an output current level up to 1.5A. The regulated output voltage can be selected among 32 preset values from 0.5V to 3.6V in steps of 100mV, or it can be obtained with a pair of external resistors. The circuit integrates complex analog and digital control blocks providing state of the art features such as UVLO protection, chip enable control, soft start-up and soft shut-down, hiccup short-circuit protection, customer selectable thermal shut-down, input power supply protection, output overshoot remover and stability over an extremely wide range of load capacitances. The circuit offers a fair ±2% absolute accuracy and is guaranteed latch-up free. The second product is an advanced high-temperature, low-power, digitally trimmable voltage reference (XTR75020). Thanks to a custom, 1-wire serial interface, the absolute precision and the temperature coefficient can be adjusted in order to obtain an accuracy better than 0.5% with a temperature coefficient bellow ±20ppm/°C. On-chip OTP memory for trimming of absolute value and temperature coefficient makes the circuit extremely accurate and almost insensitive to drifts over time and temperature. The circuit features a class AB output buffer able to source or sink up to 5mA and remains stable with any load capacitance up to 50μF. The XTR75020 has nine preset possible output voltages. The source and sink short circuit current always remains bellow 25mA. The quiescent current consumption is 300μA typical at 230°C while the standby current is, in all cases, under 20μA. Both devices are designed on a latch-up free silicon-on-insulator process.

This paper presents the problematic associated to the design of a complete motor drive, exposing all available and missing blocks at this moment. We proceed by dividing the power drive into basic functions – control, different power supplies, isolated communication, controller interfacing, current monitoring – and we present for each of these functions an implementation example. Implementation examples shown are based on high-temperature X-REL parts such as XTR26020 Isolated Intelligent Gate Driver, XTR40010 Isolated Two Channel Transceiver, XTR30010 PWM Controller, XTR70010 and XTR70020 Low-dropout Linear Regulators and XTR50010 Bidirectional Multichannel Level Translator. A drive solution based on the XTR26020, presented for the first time in this paper, is explained and compared against previous art. Main characteristics of the new linear regulator XTR70020 are presented, showing the best-in-class dropout voltage, which outperforms the closest competitor by a factor of three. For all parts featured, tests results at an ambient temperature up to 230°C (even higher in some cases) are presented.

Knowledge of frame loads at the limits of the intended driving conditions is important during the design process of a vehicle structure. Yet, retrieving these loads is not trivial as the load path between the road and the frame mounting point is complex. Fortunately, recent studies have shown that multibody dynamic (MBD) simulations could be a powerful tool to estimate these loads. Two main categories of MBD simulations exist. Firstly, full analytical simulations, which have received great attention in the literature, are run in a virtual environment using a tire model and a virtual road. Secondly, hybrid simulations, also named semi analytical, uses experimental data from Wheel Force Transducers and Inertial Measurement Units to replace the road and tire models. It is still unclear how trustworthy semi analytical simulations are for frame load evaluation. Both methods were tested for three loads cases. It was found that semi analytical simulations were slightly better in predicting vehicle dynamic and frame loads than the full analytical simulations for frequencies under the MF-Tyre model valid frequency range (8 Hz) with accuracy levels over 90%. For faster dynamic maneuvers, the prediction accuracy was lower, in the 50%–80% range, with semi analytical simulations showing better results.