Figure 4

Left and right spacing deviation of the advance hydraulic support: (a) Ideal supporting state; (b) non-ideal supporting state (left avertence); and (c) non-ideal supporting state (right avertence).

Left and right spacing deviation of the advance hydraulic support: (a) Ideal supporting state; (b) non-ideal supporting state (left avertence); and (c) non-ideal supporting state (right avertence).