= Kris Hauser
{c}
<Kris Hauser> is a <roboticist> whose research concerns <robot motion planning> and control. The University of Illinois identifies him as a professor working across computing and engineering, with research on decision-making for physical robots under limits such as uncertain dynamics and bounded computation.<Kris Hauser profile by the University of Illinois>[Biography, robot planning/control and computational constraints]{ref}
His identified https://siebelschool.illinois.edu/about/people/department-faculty/kkhauser[university profile] provides an external https://ws.engr.illinois.edu/directory/viewphoto.aspx?photo=19910&s=300[portrait of Kris Hauser].
His author-hosted <Robotic Systems by Kris Hauser> brings geometry, motion selection and contact mechanics into one technical account. Its contact-planning treatment explains why selecting contact and selecting motion are coupled: making or breaking contact changes the constraints on the <robot>.<Robotic Systems by Kris Hauser>[Chapter 12, Manipulation planning and locomotion planning; Contact modeling]{ref} A collision-free <trajectory> alone does not establish that the available contacts can produce the required <forces>.
An original static planar example makes that distinction quantitative. Suppose two nonadhesive point contacts support a body of <gravitational weight> $W=200\,\mathrm N$ at horizontal positions $x_1=0$ and $x_2=0.5\,\mathrm m$. With <center of mass> coordinate $x_c$ and no other applied force or moment, vertical force and <torque> balance give
$$
F_1+F_2=W,\qquad 0.5F_2=Wx_c.
$$
At $x_c=0.20\,\mathrm m$, the normal reactions are $F_1=120\,\mathrm N$ and $F_2=80\,\mathrm N$. Moving the center to $x_c=0.60\,\mathrm m$ while retaining those same contacts would require $F_1=-40\,\mathrm N$ and $F_2=240\,\mathrm N$. A negative normal reaction violates the nonadhesive contact model. A planner must change the motion, contacts or assumed external forces; a path that avoids obstacles need not satisfy support constraints.
This is a derived example of the modeling question, not an experiment attributed to Hauser. His text supplies the explicit unilateral-contact and equilibrium framework.<Robotic Systems by Kris Hauser>[Chapter 12, Equilibrium conditions and horizontal support-polygon discussion]{ref} A proposed robot test compares predicted reactions with calibrated contact measurements while shifting a controlled load, recording any change of contact rather than forcing the original static model onto a changed apparatus.
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