Evaluation of Velocity Estimation Methods Based on Their Effect on Haptic Device Performance

2019

Energies

In the serial hybrid electric propulsion system of a small propeller aircraft the battery state of charge is fluctuating due to the diversity of possible power flows. Overwhelming visual information on the cockpit displays, besides requiring visual pilot attention, increases pilot workload, which is undesirable, especially in risky flight situations. Haptic interfaces, on the other hand, can provide intuitive cues that can be applied to enhance and simplify the cockpit. In this paper, we deal with an enhanced power lever stick, which can provide feedback force feel with haptic cues for enhanced information flow between the pilot and the powertrain system. We present selected haptic patterns for specific information related to the fluctuating battery state of charge. The haptic patterns were designed to reduce pilot workload, and for easy use, safe and energy-efficient control of the hybrid electric powertrain system. We focus on the advanced control design for high-performance force feedback required for rendering fine haptic signals, which stimulates the sensitive haptics of a pilot’s hand-arm system. The presented control algorithm has been designed by the sliding mode control (SMC) approach in order to provide disturbance rejection and high-fidelity haptic rendering. The proposed control design has been validated on an experimental prototype system.

Section: Frictionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Advanced Control Approach based on SMC Design for the High-Fidelity Haptic Power Lever of a Small Hybrid Electric Aircraft

2019

Energies

“…Thus, since incremental encoders can only generate a pulse train with its frequency related to the shaft velocity, a suitable estimation algorithm should be applied in order to obtain smooth velocity information. Although there has been extensive past research related to this issue over the past few decades [26,27], new emerging applications in robotics and other areas with cutting-edge requirements foster further intensive research in this field, e.g., the motion control of hydraulic actuators [28], pneumatic actuators [29], haptic interfaces [30], mobile robots [31], robot manipulators [32], humanoid robots [33], and collaborative robots for safe physical human-robot interaction [34], automotive applications [35], etc. Since the performance of a velocity control loop is related strongly to the quality of the velocity feedback information, achieving a smooth, high-bandwidth velocity estimate, which is required for oscillation-free high-bandwidth control loops, still presents quite a challenge.…”

Section: Introductionmentioning

confidence: 99%

The Improved Division-Less MT-Type Velocity Estimation Algorithm for Low-Cost FPGAs

2019

Electronics

Advanced motion control applications require smooth and highly accurate high-bandwidth velocity feedback, which is usually provided by an incremental encoder. Furthermore, high sampling rates are also demanded in order to achieve cutting-edge system performance. Such control system performance with high accuracy can be achieved easily by FPGA-based controllers. On the other hand, the well-known MT method for velocity estimation has been well proven in practice. However, its complexity, which is related to the inherent arithmetic division involved in the calculus part of the method, prevents its holistic implementation as a single-chip solution on small-size low-cost FPGAs that are suitable for practical optimized control systems. In order to overcome this obstacle, we proposed a division-less MT-type algorithm that consumes only minimal FPGA resources, which makes it proper for modern cost-optimized FPGAs. In this paper, we present new results. The recursive discrete algorithm has been further optimized, in order to improve the accuracy of the velocity estimation. The novel algorithm has also been implemented on the experimental FPGA board, and validated by practical experiments. The enhanced algorithm design resulted in improved practical performance.

“…Advanced motion control applications require highly accurate wide-range velocity information with high-bandwidth [ 1 , 2 , 3 , 4 ]. A typical motion control system consists of a motorized drive, a feedback device and a controller.…”

Section: Introductionmentioning

confidence: 99%

“…However, due to the discrete nature of the incremental encoder operating as a pulse generator, a straightforward approach for velocity estimation results in highly noisy data that cannot usually be applied directly in the control loop. Though the noise component can be filtered out, this approach causes a phase lag that is undesired in high-performance closed-loop control in the applications of robotics or haptic interfaces [ 3 , 4 , 7 ].…”

Section: Introductionmentioning

confidence: 99%

Accurate FPGA-Based Velocity Measurement with an Incremental Encoder by a Fast Generalized Divisionless MT-Type Algorithm

Čurkovič

2018

Sensors

Velocity measurement by an incremental encoder is an important issue for advanced motion control applications such as robotics. In this paper, we deal with a kind of MT-type velocity estimation method. Though the conventional MT method is well known and has been well proven in practice, it requires execution of an arithmetic division operation that prevents an efficient implementation on low-cost FPGA-based control platforms. Thus, we propose a divisionless MT-type algorithm, which can provide a similar performance in velocity estimation accuracy as the conventional method, but requiring significantly less FPGA resources, since it implements only simple arithmetic operations such as addition, subtraction, and multiplication, that can be implemented more easily on the processing hardware. Furthermore, the algorithm is fast in execution, thus, it provides the output in only a few clock cycles. Though the proposed algorithm can be described in a recursive form, the stability of the estimation process is not jeopardized, although it is an important issue in this case. Hence, the algorithm is introduced in a form which assures stability in a wide speed range. We show the implementation of the algorithm on the experimental FPGA platform. The experimental results validated the proposed divisionless MT-type algorithm fully for accurate velocity estimation.