IFAC-PapersOnLine 49-19 (2016) 078–083 ScienceDirect Available online at www.sciencedirect.com 2405-8963 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Peer review under responsibility of International Federation of Automatic Control. 10.1016/j.ifacol.2016.10.465 © 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved. Keywords: shared control, haptic aid, force feedback, motor control 1. INTRODUCTION Operating a vehicle is a difficult task that requires a high level of cognitive resources. Automated systems have been introduced to assist human operators during control tasks, see Wickens et al. (1998). When automated systems take over the biggest part of a control task, operator’s role may be reduced to monitoring the automated system, with the risk of a decreased situational awareness, and ability of understanding the system state for intervening in the control loop when needed, see Endsley and Kiris (1995) and Kaber and Endsley (1997). Haptic aids and the shared control paradigm have been put forth as an appropriate solution to these issues, see Abbink et al. (2008, 2012); De Stigter et al. (2007); Goodrich et al. (2011); Olivari et al. (2014). In addition to the use as an operational aid, shared control could also be considered as a support to training, see Maimeri et al. (2016). Unfortunately design of a haptic aid for shared control is not straightforward and much research is still needed in this field, see for example the many different approaches reviewed in Pe- termeijer et al. (2015), and the complementary techniques named Direct and Indirect Haptic aid, in short DHA and IHA, presented in Alaimo et al. (2010); other interesting reads on this are: Abbink et al. (2008); Mulder (2007). Experimental campaigns with human subjects and haptic devices are the tools used to provide scientific evidence of otherwise only good conjectures. A large variety of, some- times relatively cheap, commercial haptic devices, mainly designed for general purpose haptic interaction with vir- tual worlds, exists. These devices are not well suited for shared control studies since they have shapes, handles, and volumes of motion that are typically very different from the control devices found in vehicles. A smaller niche of haptic devices instead is constituted by force-feedback capable control inceptors that resemble and have the same operational functionality of real vehicle input devices, like steering wheels (Profumo et al., 2013), helicopter cyclic (Nieuwenhuizen and B¨ ulthoff, 2014), pedals (Abbink et al., 2008) and airplane sidesticks (Olivari et al., 2015). These types of device are better suited for man in the loop studies where shared control of vehicles, or of machines in general, is considered; unfortunately, due to belonging to a market niche, the price of commercial products like these is usually high. In order to improve the possibility to perform large shared control experimental campaigns, at a lower price, a novel 2 DOFs haptic stick was designed and realized at University of Pisa with accuracy and cost in mind. A cheap commercial off-the-shelf force-feedback enabled joystick, sold for the gaming market, was modified in order to allow the degree of accuracy needed by haptic experiments. This work is part of an ongoing work aiming at realizing a 4 DOFs haptic stick. The paper is organized as follows: Section 2 presents the modified joystick architecture, the results of open loop identification tests, and a preliminary closed loop validation. Section 3 presents the results of the multi-sine Lorenzo Pollini * Matteo Razzanelli * Mario Olivari ** Alessandro Brandimarti * Michele Maimeri * Paolo Pazzaglia * Giovanni Pittiglio * Roger Nuti * Mario Innocenti * Heinrich B¨ ulthoff ** * University of Pisa, Pisa, Italy. ** Max Planck Institute for Biological Cybernetics, Tuebingen, Germany Abstract: Shared control is becoming widely used in many manual control tasks as a mean for improving performance and safety. Designing an effective shared control system requires extensive testing and knowledge of how operators react to the haptic sensations provided by the control device shared with the support system. Commercial general purpose haptic devices may be unfit to reproduce the operational situation typical of the control task under study, like car driving or airplane flying. Thus specific devices are needed for research on specific task; this market niche exists but is characterized by expensive products. This paper presents the development of a complete low cost haptic stick, of its initial characterization and inner loop and impedance control systems design, and finally proposes an evaluation with two test cases: pilot admittance identification with the classical tasks, and an entire haptic experiment. In particular this latter experiment tries to study what happens when a system failure happens in a pilot support system built using a classical embedded controller, compared to a system built following the haptic shared control paradigm. Design, Realization and Experimental Evaluation of a Haptic Stick for Shared Control Studies