A scanning system for inspecting composite structures having internal cavities with soft tooled radii, the scanning system comprising: a support assembly comprising a plurality of wheels; a scanner assembly; a sensor: wherein said scanner assembly comprises: a pivotable subassembly pivotably coupled to said support assembly for pivoting about a sweep axis; and a sensor position adjustment subassembly translatably coupled to said pivotable subassembly, said pivotable subassembly comprising first and second linear motion guide halves and said sensor position adjustment subassembly comprising third and fourth linear motion guide halves coupled to said first and second linear motion guide halves respectively to guide said sensor position adjustment subassembly to move linearly relative to said pivotable subassembly in a direction normal or nearly normal to said sweep axis; and wherein said sensor position adjustment subassembly further comprises a sensor holder that holds said sensor and is pivotably coupled to said third and fourth linear motion guide halves; a first motor mounted to said support assembly and coupled to said scanner assembly, said first motor driving pivoting of said scanner assembly when actuated; a tractor vehicle which is driven by a second motor mounted thereon, wherein the second motor causes said support assembly to move when actuated, and wherein said support assembly and said tractor vehicle comprise respective sets of magnets (36, 28) which are magnetically coupled, the attraction force between magnets on said support assembly and said tractor vehicle being strong enough that the driven tractor vehicle pulls the support assembly; and a motor controller programmed to control said first and second motors to operate in a synchronized manner such that a velocity of said support assembly depends on a length of said sensor and a cycle rate and sweep angle range of said scanner assembly. a support assembly comprising a plurality of wheels; a scanner assembly; a sensor: wherein said scanner assembly comprises: a pivotable subassembly pivotably coupled to said support assembly for pivoting about a sweep axis; and a sensor position adjustment subassembly translatably coupled to said pivotable subassembly, said pivotable subassembly comprising first and second linear motion guide halves and said sensor position adjustment subassembly comprising third and fourth linear motion guide halves coupled to said first and second linear motion guide halves respectively to guide said sensor position adjustment subassembly to move linearly relative to said pivotable subassembly in a direction normal or nearly normal to said sweep axis; and wherein said sensor position adjustment subassembly further comprises a sensor holder that holds said sensor and is pivotably coupled to said third and fourth linear motion guide halves; a pivotable subassembly pivotably coupled to said support assembly for pivoting about a sweep axis; and a sensor position adjustment subassembly translatably coupled to said pivotable subassembly, said pivotable subassembly comprising first and second linear motion guide halves and said sensor position adjustment subassembly comprising third and fourth linear motion guide halves coupled to said first and second linear motion guide halves respectively to guide said sensor position adjustment subassembly to move linearly relative to said pivotable subassembly in a direction normal or nearly normal to said sweep axis; and wherein said sensor position adjustment subassembly further comprises a sensor holder that holds said sensor and is pivotably coupled to said third and fourth linear motion guide halves; a first motor mounted to said support assembly and coupled to said scanner assembly, said first motor driving pivoting of said scanner assembly when actuated; a tractor vehicle which is driven by a second motor mounted thereon, wherein the second motor causes said support assembly to move when actuated, and wherein said support assembly and said tractor vehicle comprise respective sets of magnets (36, 28) which are magnetically coupled, the attraction force between magnets on said support assembly and said tractor vehicle being strong enough that the driven tractor vehicle pulls the support assembly; and a motor controller programmed to control said first and second motors to operate in a synchronized manner such that a velocity of said support assembly depends on a length of said sensor and a cycle rate and sweep angle range of said scanner assembly.