Figure 2 shows the schematic diagram of the i-th manipulator (finger) contacting the object at the point (p_{c_i}).
The (unsigned) distance from the COM of the snake robot to the contact point is denoted by |COM|, and the angle between this vector and the link contacting the object is denoted as (angle {COM}).
When an object is placed on a liquid, its weight Fw depresses the surface, and is balanced by the surface tension forces on either side Fs, which are each parallel to the water's surface at the points where it contacts the object.
The whisker contacts the object at the point (x obj, y obj) at an angle θ obj.
Grasp stability is the result of selecting appropriate grasp sites on an object, defining hand preshaping, transporting the hand to enable the digits to contact the object, and, once in contact with the object, avoiding slippage by applying sufficient surface-normal forces in relation to any destabilizing surface-tangential forces at the individual digit-object interfaces.
No influence of rank or age was found for the latencies to contact the object, the durations of investigating or manipulating in the pack condition (Tables A19, A20, A21).
Positive reinforcement is given by the realization of a stable grasp of the target object, and negative reinforcement is given for grasps that do not contact the object or are unstable enough to allow the object to slip from the hand.
While studies of parietal representation of object location test the encoding of the center of a visual target, reach-to-grasp movements direct the wrist to some region offset from this point so that the hand may contact the object's affordances appropriately.
When the object is close to the face (small d), the whisker contacts the object near its base and a static solution exists for most practical θp values (peak-to-peak amplitude of whisker movements, 50° [ Voigts et al., 2008; Curtis and Kleinfeld, 2009; O'Connor et al., 2013]).
There were significant overall genotypic differences in contacting the objects (monkey: F 1,23) = 8.6, P<0.01; zebra: F 1,23) = 5.9, P<0.05; and horse: F 1,23) = 8.7, P<0.01) with IL-6-deficient animals making more overall contacts than wild-type mice.
